Quantitative blood flow velocity imaging using laser speckle flowmetry

Abstract

Laser speckle flowmetry suffers from a debated quantification of the inverse relation between decorrelation time ( τ _c ) and blood flow velocity ( V), i.e. 1/ τ _c  = α V. Using a modified microcirculation imager (integrated sidestream dark field - laser speckle contrast imaging [SDF-LSCI]), we experimentally investigate on the influence of the optical properties of scatterers on α in vitro and in vivo. We found a good agreement to theoretical predictions within certain limits for scatterer size and multiple scattering. We present a practical model-based scaling factor to correct for multiple scattering in microcirculatory vessels. Our results show that SDF-LSCI offers a quantitative measure of flow velocity in addition to vessel morphology, enabling the quantification of the clinically relevant blood flow, velocity and tissue perfusion.