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. Small-angle X-ray scattering tensor tomography (SAXS-TT) is a promising technique for non-destructive, stain-free imaging of brain samples, enabling quantitative studies of myelination and neuron orientations, i.e. of nano-scale properties imaged over centimeter-sized samples.