Medical Design Briefs - October 2023 - 50

5.6 cm
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Width
Visible Light
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5.45 cm
1.72 cm
terial fluorescence was present were considered
" non-inflamed, " while wounds
that were slightly warmer than healthy
skin and had no or slight bacterial fluorescence
were considered " inflamed. "
The last two patterns - wounds that
were substantially warmer, with or without
bacterial fluorescence - were both
designated as " infected, " because all
the clinicians who had examined these
wounds had considered them infected.
Out of the 66 wounds, 20 were considered
noninflamed, 26 were inflamed,
and 20 were infected.
The researchers performed principal
component analysis and used an algorithm
called nearest k-neighbor clustering
to see whether a machine learning model
could accurately identify these different
categories of wound. They found
that the model could identify all three
very well, with an overall accuracy of 74
percent. When differentiating between
infected vs. noninfected wounds, the
model correctly identified 100 percent
of infected wounds and 91 percent of
noninfected wounds.
Bacteria
Thermal Imaging Bacterial Fluorescence
The Swift Ray 1 imaging device is a pocket-sized hyperspectral camera that is designed to sit over a
smartphone's camera lens and wirelessly connect to Swift Medical's Skin and Wound app. Once connected,
the camera allows the simultaneous acquisition of: visible light images that can be used for clinical
inspection, wound area measurement, and the automated identification of tissue types present in the
wound; infrared thermal images for the assessment of vascular and inflammatory patterns; and bacterial
fluorescence images for the assessment of bacterial bioload in wounds. (Credit: Frontiers in Medicine)
(which measure body heat), and bacterial
fluorescence images (which reveal
bacteria using violet light).
None of these images would be enough
to identify infection alone. Clinical inspection
has low accuracy, as does thermography
measuring heat changes caused by
inflammation and infection. Bacterial fluorescence
can only look at the surface of
a wound, which is naturally contaminated
with bacteria, so additional methods are
needed to differentiate between contamination
and an infected wound.
" Research has demonstrated bacterial
imaging helps guide clinicians' work to remove
nonviable tissue, yet it cannot identify
infection by itself, " explains Dr. Jose
Ramirez-GarciaLuna of McGill University
Health Centre, first author of the study.
" Thermography provides insight into the
inflammatory and circulatory changes happening
under the skin. "
50
The scientists sought to combine
these modalities to come up with a
method which wouldn't need multiple
expensive devices, would overcome the
weaknesses of each imaging method,
and could provide an objective measure
of wound healing.
To test their device, they recruited 66
wounded patients. Their wounds showed
no sign of infection spreading further, did
not contain foreign bodies, and had not
previously been treated with antibiotics or
growth factors. The patients' wounds were
uncovered, cleaned, and dried before imaging,
and afterwards cared for as usual.
n A Picture of Health
The images were reviewed by a researcher
who wasn't present for the
wound care process. Four patterns were
identified. Wounds where the wound was
not warmer than healthy skin and no bacwww.medicaldesignbriefs.com
n
A New Tool in the Box
The researchers pointed out that the
images should always be considered in
their medical context. For instance, a
wound that is cool enough to be categorized
as noninflamed could have a limited
blood supply, compromising healing.
But because the Swift Ray 1 combined
with the Swift Skin and Wound software
allows doctors to combine multiple
modalities of identifying infection,
it increases the tools available to them
without demanding the use of several expensive
devices. In the future, the device
could make it possible to secure a rapid,
accurate diagnosis for every wounded
patient and enable more effective telemedicine
assessments.
" This was a pilot study, and follow up
studies are planned, " cautions Fraser.
" In the future, patient populations with
more wound types are required to validate
across populations. "
Reference
1. " Jose L. Ramirez-GarciaLuna, et al., " Is my Wound
Infected? A Study on the Use of Hyperspectral
Imaging to Assess a Wound's Infectious Status, "
Frontiers in Medicine, https://www.frontiersin.org/
articles/10.3389/fmed.2023.1165281/full
For more information, e-mail Robert
D. Fraser at rob.fraser@swiftmedical.
com or visit www.frontiersin.org.
Medical Design Briefs, October 2023
4.6 cm
4.3 cm

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Medical Design Briefs - October 2023

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