PS-DSCI
Programmable scanning diffuse speckle contrast Imaging . Supported by theNIH, we have developed a low-cost, portable PS-DSCI technology (US Patent #18/985,503) for fast, high-density, and depth-sensitive imaging of CBF in rodents. The PS-DSCI employed a programmable digital micromirror device (DMD) for remote line-shaped laser (785 nm) scanning on tissue surface and synchronized a 2D camera for capturing boundary diffuse laser speckle contrasts. New algorithms were developed to address deformations of line-shaped scanning, thus minimizing CBF reconstruction artifacts. The PS-DSCI was examined in head-simulating phantoms and adult mice. The PS-DSCI enables resolving intralipid particle flow contrasts at different tissue depths. In vivo experiments in adult mice demonstrated the capability of PS-DSCI to image global/regional CBF variations induced by 8% CO2 inhalation and transient carotid artery ligations.
(Faezeh Akbari, Xuhui Liu, Fatemeh Hamedi, Mehrana Mohtasebi, Lei Chen, Guoqiang Yu, “Programmable scanning diffuse speckle contrast imaging of cerebral blood flow,” Neurophoton. 12(1) 015006 (27 January 2025).)
Fig. 1: PS-DSCI system. (a) The distribution of diffraction orders and energy envelope reflected by the DMD, which are dependent on the angle of incidence (θi) and angle of reflection (θr ).θr represents the center of energy envelope distribution. (b) Schematic of the PS-DSCI prototype. (c) A photo of the PS-DSCI prototype.
Fig. 2 Point scanning (scDCT) versus line scanning (PS-DSCI). In contrast to 2500 scanning points (S1 to S2500) by scDCT, PS-DSCI scans the same ROI with 100 scanning lines (L1 to L50, along vertical and horizontal directions, respectively).
Fig. 3 Depth-sensitive 2D mapping of intralipid particle flow in head-simulating phantoms. (a) Bottom view of fabricated solid phantom with the infinity-shaped channel, designed to be filled with the liquid phantom. (b) Top view of the fabricated phantom. (c) The selected camera FOV and scanning ROI on the top of the phantom. (d) The SNR distribution with varied S-D separations (1 to 6 mm) and detector-belt thicknesses (1 to 6 mm) for the phantom with top layer thickness of 1 mm. (e) The SNR distribution with varied S-D separations (1 to 6 mm) and detector-belt thicknesses (1 to 6 mm) for the phantom with top layer thickness of 2 mm. (f) The 2D flow map of head-simulating phantom with the top layer of 1 mm thickness. The S-D separation and detector-belt thickness for flow map reconstruction were 4 and 2 mm, respectively. (g) The 2D flow map of the head-simulating phantom with the top layer of 2 mm thickness. The S-D separation and detector-belt thickness for flow map reconstruction were 5 and 4 mm, respectively.
Fig. 4 Two-dimensional maps of BFI at different depths in a representative mouse (mouse #7). (a) The selected ROI for BFI mapping on the exposed skull with its scalp retracted. (b) The speckle image with a vertical scanning line on the ROI. (c) The speckle image with a horizontal scanning line on the ROI. (d) 2D maps of BFI with varied S-D separations of 1 to 3 mm and detector-belt thicknesses of 1 to 3 mm.
Fig.5 Continuous mapping of rCBF variations during 8% CO2 inhalations and transient carotid artery ligations in mice with intact skulls. (a) BFI maps and time-course rCBF changes before, during, and after 8% CO2 inhalation in an illustrative mouse (mouse #8). The dash lines separate 10 min of baseline, 5 min of CO2 inhalation, and 10 min of recovery, respectively. The ROI for data analysis of rCBF time-course changes is shown in the first BFI map. (b) Group average time-course rCBF changes during 8% CO2 inhalations in eight mice (mouse #1 to mouse #8). The error bars represent standard errors. (c) BFI maps and time-course rCBF changes during transient carotid artery ligations in an illustrative mouse (mouse #8). The dash lines separate the 5 min of baseline, 3 min of right carotid artery ligation, 1 min of bilateral ligation, 3 min of left carotid artery release, and 5 min of right carotid artery release. The ROI of LH and RH for data analyses of rCBF time-course changes are shown in the first BFI map. (d) Group average time-course rCBF changes during transient carotid artery ligations in seven mice (mouse #1 to mouse #4 and mouse #6 to mouse #8). The error bars represent standard errors.