Interpretation of Near-Infrared Imaging in Acute and Chronic Wound Care
SnapshotNIR uses NIR (Near-Infrared) light to determine tissue oxygenation saturation (StO2), one of the key indicators of tissue health. NIR light penetrates ~2-3mm into the tissue, making it ideal for microcirculation assessment, where oxygen exchange is happening. Key Publications in Wound Care covers some of the most up-to-date research on the use of Kent Imaging’s SnapshotNIR in the areas of wound care and limb preservation.
Interpretation of Near-Infrared Imaging in Acute and Chronic Wound Care. Diagnostics. 2021;11(5).
Arnold J, Marmolejo VL.
CLINICAL DATA
Background: Vascular assessment is a critical component of wound care. Current routine non-invasive vascular studies have limitations that can give a false sense of security that there is adequate perfusion for healing. Near-infrared imaging modalities can serve as an additional diagnostic assessment of wounds in which adequate perfusion is a concern. The correct interpretation of near-infrared images is paramount as subtleties exist in the acute and chronic wound populations that can lead to confusion. The objective of this paper is to educate providers on the correct interpretation of near-infrared images in day-to-day wound care practice to guide clinical decision-making.
Methods: The authors explore factors that contribute to delayed wound healing (e.g., localized ischemia, infection), factors that affect tissue thickness (e.g., edema, atrophic tissue, products within the wound bed), and factors that affect local vasculature (e.g., hyperbaric oxygen therapy, local anesthetics, epinephrine). They then suggest ways to monitor wound progression and how near-infrared imaging can guide clinical decision-making (e.g., wound bed preparation and preoperative planning, supporting information for vascular intervention, and assessing how patients respond to treatment).
Figure 1. (A) Baseline clinical photograph; and (B) near-infrared image assessment of the left dorsal foot. Note on the near-infrared image the increased signal on the dorsum of the foot secondary to skin and soft tissue infection. (C) Clinical photograph; and (D) near-infrared image assessment following initiation of antibiotic therapy. Note the reduction of signal on the dorsal foot following initiation of antibiotic therapy.
Figure 2. (A) Baseline clinical photograph; and (B) near-infrared image assessment of the left dorsal foot in a patient with arterial insufficiency referred by hyperbaric oxygen therapy. Note reduced signal to the dorsal foot (C) immediately prior to a single session of hyperbaric oxygen therapy and immediately following (D) this treatment.
Conclusion: Near-infrared images in acute and chronic wound care go beyond simple interpretation of whether tissue is perfused or not. Drawing on extensive experience, this paper highlights identification patterns that remain consistent under various conditions influencing wound outcomes while pointing out nuances that may lead inexperienced users to incorrectly assess patients.