In this work we demonstrate the feasibility of applying small-angle X-ray scattering computed tomography (SAXS-CT) for non-invasive molecular imaging of myelin sheaths in a rat brain. Our results show that the approach yields information on several quantities, including the relative myelin concentration, its periodicity, the total thickness of the myelin sheaths, and the relative concentration of cytoskeletal neurofilaments. For example the periodicity of the myelin sheaths varied in the range from 17.0 to 18.2. nm around an average of 17.6 (± 0.3). nm. We believe that imaging, i.e., spatially resolved measuring these quantities could provide general means for understanding the relation to a number of neurodegenerative diseases.