Speckle image analysis of cortical blood flow and perfusion using temporally derived contrasts

Contrast values estimated from temporal statistics is used for laser speckle contrast analysis (LASCA) of cortical blood flow and perfusion. Using temporal statistics, we are able to reliably estimate the blood flow and perfusion by processing only a selected number of pixels from the raw speckle images. For the number of frames (N > 6) for estimating the temporal contrast, the root mean square (RMS) of the inverse decorrelation time (τ_c) is found to be relatively constant with a variance of ± 3.52%. For a given window size used for estimation of τ_c, it is observed that the RMS of 1/(τ_c values exhibit a low variance of ± 4.62% as compared to spatially derived contrasts (SDC) with/without averaging. For a given reduction in binning size, the image processing using the temporally derived contrasts (TDC) is found to be 1.41 times faster as compared to obtained using SDC.