Could mobile phones revolutionise chronic wound treatment?

Australian researchers are developing a contactless, thermal imaging system that uses artificial intelligence to help nurses determine the best way to treat leg ulcers without waiting to see if the wound is going to heal properly.

It’s estimated that 450,000 thousand Australians currently live with a chronic wound.

Being able to predict early on which wounds will become chronic could improve outcomes by enabling nurses to start specialised therapy as soon as possible. But current techniques rely on physically monitoring the wound area over several weeks.

New research from RMIT in Melbourne paired thermal imaging with AI.

Read more: Are machine-learning tools the future of healthcare?

The software was able to accurately identify unhealing ulcers 78% of the time, and healing ulcers 60% of the time, according to the new study published in Scientific Reports.

“Our new work that identifies chronic leg wounds during the first visit is a world-first achievement,” says lead researcher Professor Dinesh Kumar, from RMIT’s School of Engineering.

“This means specialised treatment for slow-healing leg ulcers can begin up to four weeks earlier than the current gold standard.”

Dr rajna ogrin, dr quoc cuong ngo and professor dinesh kumar holding a standard thermal imaging device
Dr Rajna Ogrin, Dr Quoc Cuong Ngo and Professor Dinesh Kumar (left to right) holding a standard thermal imaging device, similar to what was used as part of the research. Credit: RMIT University

How do you normally assess wound healing?

The work builds on previous research by the same team, which found that this method could be used to predict wound healing by week 3 after initial assessment. But they wanted to know whether healing could be predicted from the first wound assessment only, reducing any delay in treatment.

If a wound is healing normally it’s area would reduce by 50% within four weeks, but more than 20% of ulcers don’t heal in this expected trajectory and may need specialist interventions.

Venous leg ulcers (VLUs) are the most common chronic wound seen in Australia and currently, the gold standard for predicting their healing– conventional digital planimetry – requires physical contact. Regular wound photography is also less accurate because there can be variations between images due to lighting, image quality, and differences in camera angle.

But a non-contact method like thermal imaging could overcome this.

The thermal profile of wounds changes over the healing trajectory, with higher temperatures signalling potential inflammation or infection and lower temperatures indicating a slower healing rate due to decreased oxygen in the region. So, taking thermal images of wounds can provide important information for predicting how they will heal.

Thermal images of a venous leg ulcer showing healthy healing progress over three weeks. Wounds
Thermal images of a venous leg ulcer (VLUs) showing healthy healing progress over three weeks. Credit: RMIT University

What did they do?

The study collected VLU data from 56 older participants collected over 12 weeks, including thermal images of their wounds at initial assessment and information on their status at the 12th week follow-up.

“Our innovation is not sensitive to changes in ambient temperature and light, so it is effective for nurses to use during their regular visits to people’s homes,” says co-author Dr Quoc Cuong Ngo, from RMIT’s School of Engineering.

“It is also effective in tropical environments, not just here in Melbourne.”

Nurse attending to a leg wound.
Nurse attending to a leg wound. Credit: Bolton Clarke Research Institute

“Clinical care is provided in many different locations, including specialist clinics, general practices and in people’s homes,” says co-author Dr Rajna Ogrin, a Senior Research Fellow at Bolton Clarke Research Institute.

“This method provides a quick, objective, non-invasive way to determine the wound-healing potential of chronic leg wounds that can be used by healthcare providers, irrespective of the setting.”

So, what’s next?

There are a few limitations to this study. First, the number of healed wounds in the dataset was relatively small compared to unhealed wounds, and the study only investigated older people.

The authors recommend that “future research should focus on improving the predictive accuracy and customising this method to incorporate this assessment into clinical practice on a wider pool of participants and in a variety of settings.”

Kumar says that they are hoping to adapt the method for use with mobile phones.

“With the funding we have received from the Medical Research Future Fund, we are now working towards that,” he says. “We are keen to work with prospective partners with different expertise to help us achieve this goal within the next few years.”

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