TR-LSCI

Time-resolved laser speckle contrast imaging (TR-LSCI)

Time-resolved laser speckle contrast imaging (TR-LSCI; U.S. Patent Application #18/473,051, 2023) is a noncontact optical imaging device designed for depth-resolved mapping of tissue blood flow. Unlike conventional LSCI, which relies on continuous-wave illumination and CMOS/CCD cameras to measure only superficial flow (<1 mm), TR-LSCI employs picosecond-pulsed illumination with a time-gated SPAD camera to separate short and long photon paths, thereby enabling depth-resolved blood flow imaging. Standard LSCI algorithms are applied at each gate, eliminating the need for tomographic reconstruction and allowing real-time blood flow mapping across different depths. Two TR-LSCI prototypes have been assembled and successfully tested in tissue phantoms, rodent brains, and rodent skin flaps.
screenshot 2025 09 05 113608.webp

Fig. 1: TR-LSCI system for 2D imaging of CBF distributions at different depths in neonatal rats.(Fathi, Faraneh, et al. “Using the latent diffusion model to enhance time-resolved laser speckle contrast imaging (TR-LSCI) of cerebral blood flow.” Biomedical Optics Express 16.10 (2025): 3895-3911.)

 
fig. 3

Fig. 2: (a)  A system schematic of the benchtop TR-LSCI prototype. (b) 3D printed solid phantom with empty UK logo channels, fabricated by a 3D printer with the top layer thicknesses of 1 mm. The dashed square indicates the scanning ROI of 40 × 40 mm2 on the phantom surface (c) Reconstructed BFI maps obtained using the TR-LSCI at the gates of #30, #76, and #84 demonstrating its depth sensitivity. (G. Yu, F. Fathi, C. Huang, S. Mazdeyasna, M. Zhao, and L. Chen Multi-wavelength time-resolved laser speckle contrast imaging (MTR-LSCI) of tissue hemodynamics and metabolism. U.S. Utility Non-provisional Patent Application #18/473,051, 2023.)

fig. 4
Fig. 3: (a) TR-LSCI prototype for 2D mapping of CBF distributions at different depths in an adult rat. (b)  A system schematic of the TR-LSCI prototype. (c)  A system schematic of the TR-LSCI prototype.(d)  A system schematic of the TR-LSCI prototype. (Fathi, Faraneh, et al. “Time-Resolved Laser Speckle Contrast Imaging (TR-LSCI) of Cerebral Blood Flow.” IEEE transactions on medical imaging. 2025; 44:1206-1217.)