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.