Laser speckle contrast imaging for assessing microcirculation in diabetic foot disease

Diabetes Mellitus is one of the most common chronic diseases worldwide and it has been estimated that the number of people with diabetes will grow because of our lifestyle changes and longer life-expectancy. This development is disturbing because diabetes has a severe impact on the patient’s life. It can cause serious complications such as blindness, heart attacks, and strokes. Another severe and most frequently recognized complication of diabetes are diabetic foot ulcers. Diabetic foot ulcers are associated with high morbidity, mortality and healthcare costs. These consequences can even be more severe in case of diabetic foot ulcers with critical ischemia. Hence, an early and accurate diagnosis of this health condition is needed.

Today, the most common diagnosis of (critical-) ischemia is determined in clinical practice, using non-invasive measurements of blood flow in the feet, by means of assessments of the ankle pressure, toe pressure or transcutaneous oxygen pressure. Yet, these currently used non-invasive measurement techniques have various disadvantages. Therefore, research into improved ways to assess the microcirculation in people with diabetic foot ulcers is needed. This thesis tried to fill this knowledge gap by looking into the potential of novel optical imaging techniques, and in particular in the potential of Laser Speckle Contrast Imaging (LSCI), for the assessment of the microcirculation in the diabetic foot and its applicability in the clinical setting.

LSCI shows both similarities and differences with the currently used non-invasive blood pressure measurements, which is an indication that it measures perfusion in a novel and different way than the currently used techniques. However, in our cohort we have not been able to link perfusion as measured with LSCI to clinical outcome parameters such as ulcer healing or successful revascularization. Despite this current lack of applicability, this novel non-invasive optical imaging technique still offer potential to change clinical practice in the field of diabetic foot disease. For this, future research is needed to further investigate how LSCI can best be used to improve outcomes of diabetic foot ulcers.