Diffusion and relaxometry study of an excised temporal lobe from a drug-resistance epilepsy patient using in vivo and ex vivo MRI

To learn and validate MRI-based microstructure models, MRI from fixed ex-vivo tissue samples can be compared with its histological counterpart. However, translating these models to in-vivo MRI requires thorough characterisation of MR-contrast changes between in-vivo and fixed ex-vivo measurements (e.g., due to fixation). By preforming this characterisation on an epilepsy patient’s freshly excised temporal lobe, we found that diffusion parameters changed strongly whereas relaxometry parameters remained almost unchanged. Our findings provide a missing link between in-vivo and fixed ex-vivo MRI that in future can facilitate in-vivo application of MRI-based microstructure mapping like estimating iron and myelin from relaxometry parameters.