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Abstract #0491

Viable and Fixed White Matter: DTI and Microstructural Comparisons at Physiological Temperature

Simon Richardson1, 2, Bernard M. Siow1, 2, Eleftheria Panagiotaki3, Torben Schneider4, Mark F. Lythgoe1, Daniel C. Alexander5

1Division of Medicine and Institute of Child Health, UCL Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom; 2Centre for Medical Image Computing, University College London, London, United Kingdom; 3Dept of Medical Phys and Bioengineering, Centre for Medical Image Computing, University College London, London, United Kingdom; 4NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation , UCL Institute of Neurology, London, United Kingdom; 5Department of Computer Science, Centre for Medical Image Computing, University College London, London, United Kingdom


We compare fixed and viable isolated tissue (VIT) in identical conditions at physiological temperature. We acquired DTI data sets with various acquisition parameters and a rich multi-b-value diffusion weighted MR (DW-MR) dataset for microstructural tissue model fitting. DTI data demonstrated a significant increase in radial diffusivity (RD) in fixed samples in comparison to VIT. Model fitting demonstrated that similar models best explain data from both samples. We conclude from model ranking stability that fixed tissue is a reasonable model for in-vivo, although significant differences in fitted model parameters suggest that water in individual compartments within the tissues behaves quite differently.