Spatial frequency domain imaging analysis of postural perfusion regulation in diabetic and neuropathic feet: a pilot...

Prevention of neuropathy-related diabetic foot complications requires early, safe and quantifiable techniques for medical intervention. In this pilot study, the feasibility of spatial frequency domain imaging (SFDI) as a quantitative tool for plantar neuropathy risk stratification is examined.

A small pilot study was conducted with participants from four categorised demographics: Control-1 (<50 years of age); Control-2 (≥50 years of age); patients with diabetes without neuropathy (59-67 years of age); and patients with diabetes with neuropathy (56-71 years of age). Each participant went through the same postural series (prone, elevated, reclined) while SFDI of the plantar region of the foot was acquired. The images were then analysed to estimate regional perfusion metrics, including regional oxygen saturation, concentration of oxy/deoxyhaemoglobin at the third metatarsal head and median values of the foot including heel.

In all 20 participants, elevation of the foot resulted in reduced haemoglobin concentrations in both the papillary and reticular dermis layers. Patients with diabetic neuropathy were found to have higher total (both oxy/deoxy) haemoglobin content in all positions relative to other participant groups. Furthermore, these participants also had higher variance in their haemoglobin concentrations relative to healthy participants.

In this pilot study, the postural regulation of perfusion metrics appeared to be correlated with disease progression, and showed a potential application of SFDI as a noninvasive, rapid and quantitative test. Participant group data indicated further investigation into postural perfusion is recommended for earlier detection of disease and as a qualitative healing metric.