Blood flow scanner offers clearer views of tissue health

A project at Virginia Commonwealth University (VCU) has developed a non-contact dye-free infrared-based blood flow scanner, and sees a strong commercial future for its technology.

The team, under VCU's Anuradha Godavarty, is currently translating its near-infrared optical scanner (NIROS) from a validated laboratory prototype to a commercial-ready product, supported in part by funding from VCU TechTransfer and Ventures.

In its trails to date, Godavarty’s team has imaged hundreds of patients across sites in the United States and India, said VCU. There are no safety concerns with the device, as it uses only near-infrared LEDs with no radiation or ionizing energy involved.

NIROS builds on work carried out in Godavarty's previous research group at Florida International University, which studied how changes in blood oxygenation could be related specifically to the healing status of diabetic foot ulcers. Such ulcers and the circulatory complications that give rise to them can result in foot amputations, and reliable ways to assess blood flow would meet a significant clinical need.

That work led to a near-infrared spectroscopy optical imaging technique that performed spatiotemporal mapping of tissues by inducing vasoconstriction and measuring the altering oxygenation flow. An oxygenated flow parameter was developed able to differentiate non-healing from healing diabetic foot ulcers.

In several other clinical scenarios, however, there remains no simple way to confirm whether enough oxygenated blood is reaching the tissue that needs it. One example is reconstructive "free flap" surgeries, in which healthy tissue is separated from one part of the body and transplanted to an injured or unhealthy area, when the first 72 hours determine whether transplanted tissue survives.

Until now, noted Godavarty, surgeons have only been able to watch oxygen reaching the flap at discrete points, not across the entire flap area.

Tissue-perfusion imaging as a high value clinical asset

The NIROS prototype device utilized LED-based light sources at 682 and 826 nanometers, and captured the diffuse reflectance near-IR signals from the tissues of interest as a measure of blood flow. Although the initial clinical tests were only applied to diabetic foot ulcers, Godavarty's team observed a pattern: almost every patient's peripheral vasculature - the circulatory system away from the chest or abdomen - was also compromised to some extent.

"Whenever clinicians intervene surgically to open up closed peripheral arteries and vessels, they have no way to visually tell if they have good perfusion to the surface of the foot," Godavarty commented. "So we said, why don't we position this as a technology that looks at peripheral vascular compromises on a larger picture?"

That repositioning points NIROS at a far larger clinical opportunity, said VCU. The global peripheral artery disease market is already thought to be worth $7 to 10 billion, and is projected to keep climbing as populations age and diabetes rates rise. Within that market, tissue-perfusion imaging has become a high value asset in vascular labs, wound care centers and limb-salvage programs, where oxygenation determines whether a wound heals or a limb is lost.

The VCU team is now developing the NIROS device into a form conforming to regulators' requirements while retaining a user-friendly design. A Commercialization Fund award from VCU TechTransfer and Ventures will support that transition through prototype refinement, regulatory consultation and software development. 

"If you can make something that you can take to the next level of being able to see it in the clinic, that's the biggest excitement that keeps driving me," said Godavarty.