Improving the estimation of flow speed for laser speckle imaging with single exposure time

Abstract

Laser speckle contrast imaging is a full-field imaging technique for measuring blood flow by mapping the speckle contrast with high spatial and temporal resolution. However, the statically scattered light from stationary tissues seriously degrades the accuracy of flow speed estimation. In this Letter, we present a simple calibration approach to calculate the proportions of dynamically scattered light and correct the effect of static scattering with single exposure time. Both the phantom and animal experimental results suggest that this calibration approach has the ability to improve the estimation of the relative blood flow in the presence of static scattering.

Optically derived metabolic and hemodynamic parameters predict hippocampal neurogenesis in the BTBR mouse model of autism

“…Since the penetration depth of speckle imaging is comparable to that of LDF , we believe that the changes in blood flow we observed originate from the same zone. As mentioned above, in future studies we aim to validate our signal to include that originating from the hippocampus using strategies presented recently for enhanced monitoring of blood flow within tissue depth . In addition, it will be recommended to combine the study conducted here with arterial spin labeling perfusion MRI to provide quantitative measure of blood flow in the hippocampus , in order to confirm the above assumption.…”

“…The differences between measurements we observed presumably arise from the differences in sensitivity of each modality, especially in terms of penetration depth or signal contributions . In order to improve deep CBF estimation by the DW‐LSI and to decrease such discrepancies, we suggest in our ongoing research to utilize one of the following strategies: the addition of optical clearing methods , spatial filtering , wavefront shaping , diffuse speckle contrast analysis , structured illumination or the recently calibrated approach involving a single exposure time . Presently, the small number of animals used may also contribute to these anomalies.…”

Enhancing vascular visualization in laser speckle contrast imaging of blood flow using multi‐focus image fusion

“…The principle of laser speckle contrast imaging is as follows: when coherent light interacts with the biomedical tissue, the scattering light from varying position within the tissue will interfere on the imaging plane of the charge‐coupled‐device (CCD) detector, resulting in a random interference pattern known as speckle . If scattering particles (eg, red blood flow) within the tissue are moving, this will cause changes in the interference, which will appear as intensity variations at the CCD detector .…”

Pulsatile Flow Measurement by a Speckle Triangle Assessment

“…When the laser speckle contrast imaging (LSCI) technique is used to quantify the flow velocity, the range and the sensitivity of the flow speed estimation have been shown to depend on many experimental parameters such as the coherence factor β, exposure time, the static scattering, light intensity, and the camera noise [8,21,22]. For the phantom experiment, the static scattering component was removed from the surface of the microfluidic device.…”