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Relative indices of water diffusion anisotropy are equivalent in live and formalin‐fixed mouse brains
Author(s) -
Sun ShuWei,
Neil Jeffrey J.,
Song ShengKwei
Publication year - 2003
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.10605
Subject(s) - anisotropy , diffusion mri , fractional anisotropy , thermal diffusivity , white matter , nuclear magnetic resonance , fixation (population genetics) , chemistry , ex vivo , anisotropic diffusion , materials science , in vivo , magnetic resonance imaging , medicine , physics , biology , optics , radiology , thermodynamics , biochemistry , microbiology and biotechnology , gene
Formalin fixation of tissue is a common laboratory practice. A direct comparison of diffusion tensor imaging (DTI) parameters from mouse brains before (in vivo) and after (ex vivo) formalin fixation is reported herein. Five diffusion indices were examined in a cohort of seven mice: relative anisotropy (RA), directional correlation (DC), trace (Tr(D)), trace‐normalized axial diffusivity (D ∥ ), and radial diffusivity (D ⟂ ). Seven regions of interest (ROIs), including five in white matter and two in gray matter, were selected for examination. Consistent with previous findings, a significant decrease of Tr(D) was observed for all ROIs after fixation. However, water diffusion anisotropy, as defined by the indices RA, DC, D ∥ , and D ⟂ , remained unchanged after fixation. Thus, fixation does not appear to alter diffusion anisotropy in the mouse brain. This finding supports the utility of diffusion anisotropy analysis of fixed tissue. The combination of DTI measurements and standard histology may shed light on the microstructural determinants of diffusion anisotropy in normal and disease states. Magn Reson Med 50:743–748, 2003. © 2003 Wiley‐Liss, Inc.