Monitoring of tissue optical properties using OCT: Application for blood glucose analysis

Noninvasive monitoring of tissue optical properties in real time could significantly improve diagnostics and management of various diseases. Recently we proposed to use high-resolution Optical Coherence Tomography (OCT) technique for measurement of tissue scattering coefficient at the depth of up to 1 mm. Our pilot studies performed in vitro and in vivo demonstrated that measurement of tissue scattering with this technique can potentially be applied for noninvasive monitoring of blood glucose concentration. High resolution and coherent photon detection of the OCT technique allowed detection of glucose-induced changes in the scattering coefficient. In this paper we report results of in vivo studies performed in dog, New Zealand rabbits, and first human subjects. OCT system with the wavelength of 1300 nm was used in our experiments. OCT signal slope was measured and compared with actual blood glucose concentration. Bolus glucose injections and glucose clamping administrations were used in animal studies. OCT signals were recorded from human subjects during oral glucose tolerance tests. Results obtained from both animal and human studies show good correlation between slope of the OCT signals and actual blood glucose concentration measured using standard glucometers. Sensitivity and accuracy of blood glucose concentration monitoring with the OCT is discussed. Obtained results suggest that OCT is a promising technique for noninvasive monitoring of tissue analytes including glucose.