Microvascular Blood Flow with Laser Speckle Contrast Imaging: Analysis of Static Scatterers Effect through Modelling and Simulation

Laser speckle contrast images (LSCI) give full-field data of surface blood flow. From LSCI, the computation of moving scatterers velocity (mainly red blood cells velocity) is possible when the modelling of the speckle contrast is performed assuming a velocity distribution for the moving scatterers. A Lorentzian distribution is often proposed. The associated mathematical expression for the speckle contrast has been studied previously. From this contrast expression, the goal herein is to simulate moving scatterers velocity values from the processing of LSCI data and to analyse the possible impact of static scatterers (like skin). For this purpose, LSCI are acquired experimentally on the forearm of twenty healthy subjects at rest, during a vascular occlusion and during reactive hyperaemia. In this study, an increase of the moving scatterers velocity is reported with the presence of static scatterers at rest, during vascular occlusion and during reactive hyperaemia. Increasing thickness of the static scattering layer has therefore an influence on moving scatterers velocities computed from LSCI.