Double-pulse laser illumination method for measuring fast cerebral blood flow velocities in the deep brain using a fiber-bundle-based endomicroscopy system

We present a new fiber-bundle-based endomicroscopy system to measure the fast cerebral blood flow (CBF) velocity in blood vessels located between the surface and the deep brain of living animals. The CBF velocity is obtained by measuring the displacement of the partially overlapped red blood cell images directly, using double-pulse 532-nm laser illumination. The proposed method could measure CBF in blood vessels with diameters ranging from 4 μm to 42 μm and could measure CBF velocities up to 3.2 μm/ms for different vessel diameters at a depth of 2.1 mm from the brain surface in a living mouse.