Anomalous proton dynamics of water molecules in neural tissue as seen by quasi-elastic neutron scattering. Impact on medical imaging techniques

Fixation is a key element for many clinical researches requiring long exposure time and resting of the tissue to avoid experimental artifacts; condition which is not easy achieved during in-vivo experiments. Several ex-vivo, e.g. post-mortem, fixation processes are commonly used, from chemical fixation to cryo-preserving methods, both having advantages and drawbacks and eventually affecting structural and dynamical properties of water within the tissue. In this paper we make use of neutron scattering technique to compare the dynamical properties of ex-vivo sections of cerebral bovine hemisphere preserved using formalin fixation and cryo-protection. Neutron scattering is a unique technique able to monitor water diffusion at atomic scale. Results suggest reduction of global water dynamics induced by the formalin fixation protocol at room temperature.