Transmissive-detected laser speckle contrast imaging for blood flow monitoring in thick tissue: from Monte Carlo simulation to experimental demonstration

Abstract

Laser speckle contrast imaging (LSCI) is a powerful tool to monitor blood flow distribution and has been widely used in studies of microcirculation, both for animal and clinical applications. Conventionally, LSCI usually works on reflective-detected mode. However, it could provide promising temporal and spatial resolution for in vivo applications only with the assistance of various tissue windows, otherwise, the overlarge superficial static speckle would extremely limit its contrast and resolution. Here, we systematically investigated the capability of transmissive-detected LSCI (TR-LSCI) for blood flow monitoring in thick tissue. Using Monte Carlo simulation, we theoretically compared the performance of transmissive and reflective detection. It was found that the reflective-detected mode was better when the target layer was at the very surface, but the imaging quality would rapidly decrease with imaging depth, while the transmissive-detected mode could obtain a much stronger signal-to-background ratio (SBR) for thick tissue. We further proved by tissue phantom, animal, and human experiments that in a certain thickness of tissue, TR-LSCI showed remarkably better performance for thick-tissue imaging, and the imaging quality would be further improved if the use of longer wavelengths of near-infrared light. Therefore, both theoretical and experimental results demonstrate that TR-LSCI is capable of obtaining thick-tissue blood flow information and holds great potential in the field of microcirculation research.

Laser speckle contrast imaging for blood flow monitoring in predicting outcomes after cerebral ischemia-reperfusion injury in mice

“…Laser speckle contrast imaging (LSCI) is a wide-field, noninvasive imaging technique with high temporal and spatial resolution, that is based on the scattering properties of moving particles (e.g., red blood cells) [ 9 ]. LSCI obtains the velocity information of the scattering particles and has been successfully used for neurovascular imaging.…”

In Situ Ratiometric Determination of Cerebral Ascorbic Acid after Ischemia Reperfusion

“…Different ischemia times were used to simulate mild, moderate, and severe brain injury in mice. The laser speckle blood flow imaging was used to evaluate the changes in the cerebral blood vessels of mice before and after modeling. − As displayed in Figure B, the left cerebral blood flow (CBF) density of the mice in the sham-operated group was evenly distributed, while the CBF density of the left brain of the MCAO mice was significantly lower than that in the sham-operated group. After 24 h of ischemia reperfusion, the CBF density of the left brain recovered to be comparable to the sham surgery group, however, the overall CBF density became higher than that of the sham-operated group.…”

Shedding light on biology and healthcare—preface to the special issue on Biomedical Optics

“…With 3D volumetric transport optical diffraction tomography and synthetic aperture, Li et al from Nanjing University of Science and Technology reported a novel label-free microscopy technique, which achieves 200 nm lateral and 500 nm axial resolution, on both cell lines and C. elegans imaging 9 . By using Monte-Carlo simulation following with experimental validation, Li et al from Huazhong University of Science and Technology have demonstrated that the transmissive-detected laser speckle contrast imaging showing superior performance over reflective-detection counterparts for blood flow monitoring in thick tissue, on different samples such as tissue phantom, animal, and human hands 10 .…”