MRI of post mortem multiple sclerosis brain: quantifying the effects of formalin fixation
Schmierer K, Tozer D, Tofts P, Miller D, Parkes H, Yousry T, Wheeler-Kingshott C, Boulby P
Institute of Neurology, UCL
Quantitative magnetic resonance imaging (qMRI) of post mortem (PM) multiple sclerosis (MS) brain is being used to probe MS. There is limited information about changes of qMRI indices in PM MS brain following fixation. We studied T1 relaxation time (T1), magnetisation transfer ratio (MTR), fraction of macromolecular protons (fB), mean diffusivity and fractional anisotropy as well as the association of qMR with pathological indices. Changes due to fixation were dependent on MR sequence used and tissue compartment (lesions, normal-appearing white matter) studied. MTR was the strongest predictor of myelin in fresh tissue whereas after fixation T1 and fB were more reliable.