Retrieving neuronal orientations using 3D scanning SAXS and comparison with diffusion MRI.

摘要: While diffusion MRI (dMRI) is currently the method of choice to non-invasively probe tissue microstructure and study structural connectivity in brain, its spatial resolution limited results need validation. Current ex vivo methods employed provide 3D fiber orientations have limitations, including tissue-distorting sample preparation, small field view or inability quantify orientation distributions. sections can be obtained from scanning small-angle X-ray scattering (3D sSAXS) by analyzing anisotropy signals. Here we adapt sSAXS for use brain tissue, exploiting high sensitivity SAXS signal ordered molecular structure myelin. We extend characterization vectors tensors, employ Funk-Radon-Transform converting information real space orientations, demonstrate feasibility thin mouse with minimal preparation. obtain a second rank tensor representing distribution function (fODF) every voxel, thereby generating fODF maps. Finally, illustrate potential comparing result same brain. show remarkably good correspondence, considering orthogonality two methods, i.e. different physical processes underlying serve as validation microstructural MRI, novel insights nervous system, given method's dMRI, myelin sheath's abundance, possibility extract myelin-specific perform micrometer-resolution scanning.