Anders Dyhr Sandgaard | Investigating mesoscopic Larmor frequency shifts from myelin and iron in ex vivo pig white matter

The project aims to test if our newly developed analytical model of the sub-voxel Larmor frequency shift in white matter incorporating mainly iron and myelin can explain the measured phase in MRI gradient echo signals. This is done by measuring the MRI signal in fixated pig optic nerve cast in agarose inside a spherical container. Agar allows us to measure the MRI signal outside the sample, which is vital to disentangle the sub-voxel frequency shift, and it keeps the optic nerve stable. Gradient echo signals will be acquired at multiple sample orientations using a bespoke coil setup developed at MPI. Additional information about axonal orientation dispersion will be estimated with diffusion MRI. The experiment will be repeated using a de-ironed optic nerve. This will allow for better disentanglement of myelin and iron magnetic susceptibility.