Diffuse reflectance spectroscopy based blood oxygenation monitoring: a prospective study for early diagnosis of diabetic foot

Diabetic foot is a serious chronic complication of diabetes mellitus affecting 15 % diabetic patients during their lifetime. Approximately 85 % lower-limb amputations are preceded by an untreated diabetic foot. Several techniques are available to diagnose foot ulceration by monitoring average blood oxygenation state of the diabetic foot. However, these techniques couldn't resolve relative local blood volume fraction of reduced/-oxyhemoglobin within the bulk of highly scattering tissue media. Therefore, the aim of this study is to extract localized blood volume fraction of reduced/- oxyhemoglobin from vascular beds of human foot. In this study, we investigated the ability of diffuse reflectance spectroscopy to quantitatively measure localized blood volume fraction of reduced hemoglobin (RHb), oxyhemoglobin (HbO₂), and oxygen saturation (SO₂) from various sites of the human foot sole. The preliminary investigation shows that the proposed approach can reliably determine the local volume fractions of RHb, HbO₂ and SO₂ in four different sites namely great toe, ball of great joint, 5th metatarsal, and calcaneum of the human foot sole. In addition, it also concludes that each part of the foot has different levels of blood volume fraction. Thus, the preliminary results suggest that this method may be used as a diagnostic tool for monitoring blood oxygenation parameters of ulcerated diabetic foot. It may help in to reduce the health-care cost and improve the quality of life of diabetic patient.