UC Irvine

Since blood flow is tightly coupled to the health status of biological tissue, several instruments have been developed to monitor blood flow and perfusion dynamics. One such instrument is laser speckle imaging (LSI). The objective of this work is to evaluate an LSI instrument employing two statistically based approaches to calculate the speckle flow index (SFI). To study the relation between SFI and the actual flow rate for the two statistical approaches, speckle images were acquired from a 0.5% blood filled tube embedded within a 5 mm thick agar gel. A syringe based infusion pump was used to inject the blood at flow rates between 0 and 5 mm/sec. We found a linear relationship between SFI and actual flow rate for both the Gaussian and Lorentzian based approaches. With the Gaussian based approach, the SFI dynamic range was up to six times larger than with the Lorentzian based approach. The Gaussian based approach is a good alternative for computation of SFI using LSI.