Myelin “insulates” our neurons enabling fast signal transduction in our brain; myelin levels, integrity, and neuron orientations are important determinants of brain development and disease. However, myelin imaging methods used in clinics or research are non-specific or destructive.
Using small-angle X-ray scattering tensor tomography (SAXS-TT), we exploited myelin’s ~17nm periodicity to non-invasively derive 3D myelin and neuron orientation maps in macroscopic tissue volumes (Figure). We demonstrated the method on a mouse brain (a-d), a mouse spinal cord, a human visual cortex and two human white matter specimens. We validated the readouts with 2D and 3D histology, and correlated the results with MRI contrasts.
read more on the PSI website
Image: Figure. a) SAXS-TT setup. b) SAXS projection of the mouse brain, with myelin signal intensity and 2D fiber orientation color-encoded. c-d) Tomographic reconstruction results in quantitative 3D myelin maps (c) and a tensor representing neuron orientations in each voxel (d). e-f) Distinct myelin periodicities in the central and peripheral nervous system (CNS/PNS) enable multiplexed imaging (e) and reconstruction (f) of CNS and PNS structures. g) Control and dysmyelinated mouse brain signals, showcasing SAXS-TT’s sensitivity in quantifying minute myelin signals (see colorbar), and myelin integrity.