Lossless temporal contrast analysis of laser speckle images from periodic signals.

Laser speckle contrast imaging is a technique that provides valuable physiological information about vascular topology and blood flow dynamics. When using contrast analysis, it is possible to obtain detailed spatial information at the cost of sacrificing temporal resolution and vice versa. Such a trade-off becomes problematic when assessing blood dynamics in narrow vessels. This study presents a new contrast calculation method that preserves fine temporal dynamics and structural features when applied to periodic blood flow changes, such as cardiac pulsatility. We use simulations and in vivo experiments to compare our method with the standard spatial and temporal contrast calculations and demonstrate that the proposed method retains the spatial and temporal resolutions, resulting in the improved estimation of the blood flow dynamics.