In vivo rat brain imaging using a short multimode fiber probe

In vivo rat brain imaging was demonstrated using the FF OCM (full field optical coherence microscopy) with SMMF (short multimode fiber) of a diameter of 125 mu m and a length of 7.33 mm. The spatial resolution was measured to be 2.0 mu m. The influences of motions for OCM images and methods to detect motions were investigated using image processing. Measurements were combinations of 3D OCM imaging (M1) with measurement time 10min and en face imaging (M2) at fixed depth with 17.9 fps and the interval time of 1 min during 30 min. For Rat 1 measured point was at the prim somatosens cortex, and the insertion length (IL) was 3.2 mm, the motions were not remarkable. En face OCM images with the region of X 56.3 mu m, Y 56.3 mu m, and Z 110 gm were measured. For Rat 2 measured point was at med parietal association cortex, and IL was 3.1 mm. Difference images and those intensity profiles showed the lateral motion of 5 mu m between two sequent en face OCM images. For both cases, 3D images similarly showed the spatial arrangement of nerve fibers. The feasibility that the motions of tissues could be detected under the SMMF using sequential difference images was shown. This might be applicable to detect the motions in deep areas in measurements such as the optical intrinsic imaging.