Vascular Imaging

1 in 10 American and British people have diabetes where 90 to 95% are type 212. Diabetes is a disorder where either not enough insulin is produced to store glucose in the liver, muscle and fat cells (Type 1), or the cells stop responding to insulin (Type 2)2. Diabetes, if left untreated, can cause diabetic neuropathy (nerve damage) and diabetic foot ulcers.

Diabetic foot ulcers are very difficult to diagnose early. Sometimes foot ulcers can go unnoticed until the ulcer becomes infected3. The ulcer development is unnoticed due to peripheral diabetic neuropathy45. The nerve damage and hypoxia are caused by narrow arteries which is difficult to determine without specialised equipment. One method of early diagnosis is vascular imaging of the foot to identify any hypoxic regions.

Hyperspectral imaging is a technique that measures “fingerprints” of a spatial area using spectroscopy6. The spatial area of interest was vasculature where oxygenated and de-oxygenated blood has different hyperspectral “fingerprints” between 500-600 nm wavelengths7. In theory, a spatial area can be analysed non-invasively by providing a tissue oxygen score and highlight regions of interest with low oxygenation. Regions of low oxygen indicate an increased likelihood of diabetic foot ulcers occurring.

This project used a low-cost 4-camera setup (model not disclosed due to outstanding intellectual property) and a custom MATLAB algorithm (code not disclosed due to outstanding intellectual property) which accounted for different camera positions, absorbance / refection of select wavelengths between 500-600 nm and a control camera that adapted to background light levels. Experimentation discovered several potential wavelength filters for the camera setup which will be taken further.

This was a successful master’s project in 2019 carried out by Diana Suciu where I was the main supervisor with Dr. Robert Barker as principal investigator at the University of Kent.

References

  1. CDC (2021) Diabetes Type 2. [Accessed 08/10/21] https://www.cdc.gov/diabetes/basics/type2.html
  2. National Health Service (NHS) UK (2021) Diabetes. [Accessed 08/10/21] https://www.nhs.uk/conditions/diabetes/
  3. Healthline (2021) Diabetic Foot Pain And Ulcers – Causes. [Accessed 08/10/21] https://www.healthline.com/health/diabetic-foot-pain-and-ulcers-causes-treatments#causes
  4. Diabetes UK (Charity) (2021) Diabetic Foot Ulcers. [Accessed 08/10/21] https://www.diabetes.co.uk/diabetes-complications/diabetic-foot-ulcers.html
  5. Diabetes UK (Charity) (2021) Diabetes Neuropathy. [Accessed 08/10/21] https://www.diabetes.co.uk/diabetes-complications/diabetes-neuropathy.html
  6. Schneider, A., & Feussner, H. (2017). Chapter 5 – Diagnostic Procedures. In Biomedical Engineering in Gastrointestinal Surgery (pp. 87–220). Academic Press. https://doi.org/10.1016/B978-0-12-803230-5.00005-1
  7. Sakota, D., Nagaoka, E., & Maruyama, O. (2015). Hyperspectral imaging of vascular anastomosis associated with blood flow and hemoglobin concentration. Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2015-Novem, 4246–4249. https://doi.org/10.1109/EMBC.2015.7319332
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