Case Study:Diabetic Ulcer Prediction
The color bar can be used to quickly identify
different regions of tissue oxygenation that then can be quantified
by using the HyperVu software. HT-oxy levels are related to color
changes (low to high, yellow to purple) – HT-deoxy levels
are related to brightness (low to high, pale to brilliant).
This 68 year old Hispanic female with type 1 diabetes had an
ulcer on her right heel and was considered at high risk for additional
ulceration. Over 2 months, she developed 2 new ulcers, one on
each foot. In each case, tissue at risk was identified by HTcOM.
The left foot ulcer & data from the two preceding visits is
shown above. Areas of lower oxygenation on the HTcOM-Oxy and HTcOM-Deoxy
color scale correlate with areas that proceeded to ulceration
on both feet. Note that on the color photo, the skin tissue appears
normal at the week 4 visit, minimally discolored but with intact
skin at the week 6 visit, and newly ulcerated at the week 8 visit.
An HT-Ulcer Prediction Index was created from the HT-Oxy and
HT-Deoxy values for each point. The HT- Ulcer Prediction Index
indicates the likelihood of ulceration with negative values (see
above).
A preliminary HT-Oxy Ulcer Prediction Ratio was also created
by comparing the HT-Oxy within a pre-ulcer area with the HT-Oxy
from a nearby site. Here, a value less than 0.75 is associated
with pre-ulcer regions as shown above.
An additional area on the plantar skin surface over the first
metatarsal is considered at high risk. This will be followed in
the additional 8 study visits.
Further algorithm development is underway. The trial design anticipates
the occurrence of at least 20 new ulcers over the course of the
study, which will provide sufficient power for appropriate statistical
analysis of the accuracy of the HT- Ulcer Prediction Index and
an HT - Ulcer Prediction Ratio. Note, the 3rd HT scan above was
performed on new hardware.
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