Clinical Applications of Near-infrared Spectroscopy in Wound Care
Roundtable Report: An Advanced Diagnostic Imaging Tool to Enhance Clinical Decision-Making and Wound Healing
Ten key opinion leaders in the wound care industry shared their knowledge in a Roundtable Report on applying near-infrared spectroscopy (NIRS) imaging technology in clinical settings. It was the unanimous opinion that using this technology can offer new diagnostic potential for clinicians, enhancing clinical decision-making and improving patient outcomes.
Three points the panel made in the report were that:
NIRS diagnostic devices can be an effective alternative to ABIs and TCOMs
Taking pre-and post-intervention images can help with determining wound response to clinical care plans
NIRS images give insight to metabolic activity and inflammatory processes beneath the surface of the wound
“A clinical examination alone is not enough to provide sufficient information about tissue oxygenation and viability.”
A non-exhaustive list of clinical applications of NIRS in the Roundtable Report included:
The panel felt that NIRS readings are especially effective with lower extremity wounds when compared to traditional assessment tools, such as ABIs or TCOMs.
Case 1: NIRS imaging as an alternative to ABIs
History: Patient with a history of stage IV prostate cancer was seen at the limb preservation clinic in September 2021, with left leg claudication and rest pain, with no paraesthesia or paralysis, status post-bilateral iliac and left femoropopliteal stenting 6 days prior.
Imaging:
CT angiography demonstrated the patient had thrombosed superficial femoral and above knee popliteal arteries.
ABI results were consistent with severe arterial insufficiency of the left leg.
While the patient’s dorsalis pedis (DP) ABI appeared normal, his posterior tibial (PT) ABI was consistent with NIRS findings of severe arterial disease (DP ABI: 1.30 and PT ABI: 0.37).
The patient had dependent rubor which often results in false readings of high oxygen in the lower extremities because of pooling. When arterial disease is suspected in a patient with dependent rubor, imaging or studies of their lower extremities should be completed in an elevated position to offset the effect of pooling.
Impact of NIRS imaging on this patient:
Earlier imaging with SnapshotNIR could have eliminated the need for an ABI in this case as it provided point-of-care imaging that demonstrated compromised blood flow in both the dorsal and plantar regions.
It is suggested that when compromised blood flow is suspected, an elevated limb image should always be taken as this procedure challenges the body to demonstrate that strong arterial flow exists.
Point-of-care imaging from SnapshotNIR for a patient that only presented once to the wound care clinic served as valuable information to the attending vascular surgeon regarding the patient’s arterial status.
Treatment plan: left lower extremity arteriogram and attempt a pharmaco-mechanical thrombectomy one day later.
The SnapshotNIR images below show a supine resting and supine elevated foot during the elevation test which can help determine PAD severity.
Left image is supine rested position, right image is supine elevated leg position after 45s. The change in StO2 at the plantar aspect of the 1st MTP was 26% (82% supine, decreasing to 56% post elevation), Deoxyhemoglobin delta was 0.05, oxyhemoglobin by 0.52, and total hemoglobin by 0.47. Images courtesy of Dr. Charles Andersen.
The panel emphasized the importance of “capturing NIRS images pre- and post-intervention which allows for the assessment of tissue response to therapy, providing quantitative information for the continuation, discontinuation or modification of treatment.”
Case 2: Using NIRS imaging to guide wound debridement
Debridement is normally used to remove eschar, necrotic tissue and callus, but it can also be used to address cellular senescence, which can be present in wounds and increases exponentially with age. Continued senescence will impair healing in patients with diabetes and cells must be injured to reinitiate an inflammatory response. Routine debridement can reinitiate an acute wound and trigger a micro-inflammation that will stimulate the wound healing processes.
Case history: 87-year-old male with Munchausen's Syndrome who presented with a scalp wound.
Imaging:
NIRS demonstrated areas of poor oxygenation within the wound.
This directed additional debridement, NIRS imaging post debridement demonstrated good oxygenation within the wound bed.
Impact of NIRS imaging on this patient:
With the demonstration of ischemic scalp tissue decreased StO2 and elevated deoxyhemoglobin values in the wound area, the NIRS imaging supported the decision to sharply debride the wound.
The deoxyhemoglobin values can be observed to decrease, matching the surrounding healthy tissue in the image captured post-debridement.
Without the NIRS images, the patient’s wound still would have been debrided along the margins to remove senescent cells, however, the debridement may not have been as thorough in removing non-viable tissue.
NIRS imaging allows us to very clearly identify non-viable tissue based on the coloration in the images and further confirms that all ischemic tissue was removed.
Treatment included continued debridement as required followed by Blastx, endoform and hydroferra blue with a mepilex border dressing. The wound went on to fully heal.
NIRS imaging allows you to re-evaluate the wound post-debridement and make sure that the intervention was complete and adequate, if you see areas of poor oxygenation then additional debridement can be performed.
Left image is pre-debridement where the area around the wound is less red, compared to the right image post-debridement that has a much greater area of red.
Panel members explained the use of NIRS to gain a better understanding of what is happening below the surface of a wound or tissue. “The wound and peri-wound StO2 values provide clinicians with an assessment of subdermal tissues involved with healing, including underlying metabolic activity and inflammation.”
Case 3: Osteomyelitis and first toe amputation
History: A 70-year-old type 2 diabetic female with neuropathy and left hallux ulceration who was followed by the limb preservation clinic for a few months for the same wound. The patient works at a restaurant and must wear close-toed, non-skid shoes and refuses offloading devices like post-op shoes or offloading boots.
Imaging:
NIRS imaging demonstrated inflammatory response extending from the medial wound to the lateral side of her hallux between the first and second toes.
Bacterial imaging documented bacteria in the wound but not in the erythematous toe - meaning bacteria autofluorescence could detect superficial bacteria but not osteomyelitis.
Clinically, erythema and swelling were observed on the whole hallux and persisted for at least 3 weeks and NIRS imaging documented significant inflammatory response consistent with osteomyelitis, providing an additional marker to suspect osteomyelitis alongside prolonged erythema, swelling and distal inflammation response.
MRI was ordered to rule out osteomyelitis, but the MRI CONFIRMED osteomyelitis
Impact of NIRS imaging on this patient:
NIRS documented significant inflammation supporting the diagnosis of osteomyelitis
“NIRS helped determine the direction for an MRI to confirm diagnosis of osteomyelitis and then also the ability to say that based on the oxygenation level, the patient will heal from a toe amputation and not require a higher level of amputation” – Dr. Charles Andersen
Treatment: A first toe amputation was performed. The patient had an uneventful post-op course and has returned to work with a shoe insert.
For amputations, NIRS imaging can determine if the patient has adequate oxygenation at the level where an amputation may be performed. SnapshotNIR can help identify ischemia by measuring the oxygenation pre-revascularization to see the roadmap of oxygenation. Following the procedure, you can measure the outcomes of the intervention (the effectiveness) and evaluate each angiosome and blood flow to the area to ensure the amputation site will heal.
“Another advantage of NIRS in this clinical scenario was to measure the oxygenation in the area at the level that you are going to amputate to make sure there is adequate oxygenation to support it.”
The clinical significance of NIRS imaging is vast. It can:
Allow the clinician to monitor the status of the wound from the day of presentation to the day of discharge
Detect changes not always visible to the naked eye
Directly influence the course of treatment during wound care
For more clinical insights from the ten key opinion leaders, read the full Roundtable Report.
Serena, Thomas, William H. Tettelbach, Andrew Rader, Amy Couch, Naz Wahab, Misael Alonso, Dan Kapp, Martha Kelso, Martin L. Johnson, and Marcus Gitterle. "An advanced diagnostic imaging tool to enhance clinical decision-making and wound healing." Journal of Wound Care (2025): 6-11.
Thank you to Dr. Charles Andersen, MD, FACS, MAPWCA, for the case examples. Dr. Andersen is the Chief of Vascular/Endovascular/Limb Preservation services (Emeritus), Chief of Wound Care Service, Madigan Army Medical Center, Tacoma, WA; Clinical Professor of Surgery UW, USUHS.