Simultaneous measurement of deep tissue blood flow and oxygenation using noncontact diffuse correlation spectroscopy flow-oximeter

We report a novel noncontact diffuse correlation spectroscopy flow-oximeter for simultaneous quantification of relative changes in tissue blood flow ( rBF ) and oxygenation (Δ[ oxygenation ]). The noncontact probe was compared against a contact probe in tissue-like phantoms and forearm muscles (n = 10) and the dynamic trends in both rBF and Δ[ oxygenation ] were found to be highly correlated. However, the magnitudes of Δ[ oxygenation ] measured by the two probes were significantly different. Monte Carlo simulations and phantom experiments revealed that the arm curvature resulted in a significant underestimation (~−20%) for the noncontact measurements in Δ[ oxygenation ], but not in rBF . Other factors that may cause the residual discrepancies between the contact and noncontact measurements were discussed and further comparisons with other established technologies are needed to identify/quantify these factors. Our research paves the way for noncontact and simultaneous monitoring of blood flow and oxygenation in soft and vulnerable tissues without distorting tissue hemodynamics.