Portable screening tool for diabetic feet can prevent amputations

TORONTO – More than 3 million Canadians have diabetes, a number that has nearly doubled since 2002 and continues to grow. These patients have tools to manage their glucose levels, but no tools to help them manage foot wounds that often lead to infection and amputation.

That’s where MIMOSA comes in.

MIMOSA (Multispectral Mobile Tissue Assessment Device) is an early-detection tool developed by Dr. Karen Cross, a surgeon scientist at St. Michael’s Hospital in Toronto, and Dr. General Leung, a magnetic resonance physicist at St. Michael’s.

The device detects poor blood circulation in the feet, which can lead to diabetic foot ulcers, by photographing the skin with near-infrared light, just beyond the range of human vision.

“It’s just above the visible region, so it’s safe, but also it has deep penetration into the skin, so it’s going to get below that top layer,” said Dr. Cross. “It can see things that we can’t, so it can see whether the skin perfused, if it has an oxygen supply, if it’s viable, and you can measure a lot of different types of molecules within this region.”

Dr. Cross likened the near-infrared light MIMOSA uses to the technology used to discover that Leonardo da Vinci was the original artist behind The Adoration of the Magi, the painting most often attributed to Filippino Lippi. The light allowed art historians to view the different layers of the painting without damaging it.

“We’re doing the same thing,” said Dr. Cross. “Before, to see how much hemoglobin you have, you’ve got to take blood. But that’s a sample. You’re damaging something by putting a needle in there. We can actually do it by not damaging anything.”

Between 15 and 25 percent of people with diabetes will have a foot ulcer at some point. These ulcers often become infected and as a result, diabetics are 23 times more likely than the general population to have a lower limb amputation. Of those who have an amputation, 30 percent die within one year. After five years, the mortality rate jumps to 70 percent.

For people with diabetes, said Dr. Cross, access to this technology could have a huge impact on their health and peace of mind.

“If we tell patients we have this technology that will be able to provide surveillance for their feet, they look at us like, ‘Where do I buy one?’ Their feet are a big concern to them, and they really have no idea how to check properly.”

The technology MIMOSA uses to monitor wounds isn’t entirely new – it was originally developed as an early detector and triage tool for determining burn depth. But what has changed is the size – perhaps the most important part for patients.

“Because of the way the technology’s changed, and because we have so much computing power in our pockets and our cell phones, we’re able to shrink it down,” said Dr. Leung. “So now it’s evolved from being ten or twelve feet tall to being a little clip-on device.”

The device is designed to work for all diabetics, no matter their age or level of mobility.

“This is something you could put on a selfie stick and put it down below and take a picture,” said Dr. Cross.

Patients can use MIMOSA to take pictures of their feet on their cell phone, according to Dr. Leung. The photos are collected via e-MIMO, MIMOSA’s e-mobile health component. They are sent to e-MIMO’s secure cloud, and from there, the team can start processing the data and see how the patients are doing.

“We can build a data bank where we’re going to be able to look at people as they’re developing these wounds,” said Dr. Leung.

The team has already seen success using MIMOSA to monitor wound development in a recently completed pilot study, and will soon begin work on a two-year, multicentre randomized controlled trial.

“We can give earlier warnings that these patients may have problems with their blood vessels and we can also do something about it through an operation, or through a dietary intervention, or change something about this patient’s lifestyle to change how the problem is going to progress,” said Dr. Leung. “We can figure out what tells us when people are starting to go downhill, and when they’re stable and okay, giving us an alert system that may help us prevent these amputations.”

It will also allow healthcare professionals to monitor their patients remotely, eliminating the need for bi-weekly hospital visits and providing access for patients in rural communities without a doctor, said Dr. Cross.

Kelly O’Brien is a communications advisor at St. Michael’s Hospital, in Toronto.