Light-Sheet Laser Speckle Imaging for 3D Vascular Visualization

Laser speckle imaging (LSI) takes advantage of wide-field, non-invasive, label-free in blood flow imaging with high spatiotemporal resolution. The traditional laser speckle imaging is a 2D vasculature mapping method, while the vasculature virtually presents a spatial distribution in vivo. To bridge the gap of conventional laser speckle imaging in vascular structure, light-sheet laser speckle imaging (LSH-LSI) is proposed due to its inherent optical sectioning capability. In this research, two label-free imaging methods are implemented where both laser speckle images and bright-field transmitted images are collected by our optical system. Laser speckle images are processed by contrast algorithm, and the red cells in transmission images are traced by particle imaging velocimetry (PIV). The pretty intricate three-dimensional vasculature in the zebrafish head and heart region was simultaneously imaged for making cross-validation by LSI and PIV. The experimental results show that the vasculature in 15 layers presents both difference and continuity. The difference demonstrates that LSH-LSI definitely has optical sectioning capability among multilayers, and the continuity suggests that superposition between different layers enables 3D vascular visualization. The axial projection is acquired by aligning the LSH-LSI vasculatures in all layers, which is consistent with the transmission PIV mapping. The primary advantage of LSH-LSI is that it has better spatial resolution than PIV. LSH-LSI has great potential to enable 3D vasculature reconstruction.