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High-resolution Structural Magnetic Resonance Imaging of the Human Subcortex In Vivo and Postmortem
Published on: December 30, 2015
Quantitative magnetic resonance of postmortem multiple sclerosis brain before and after fixation
Klaus Schmierer1, Claudia A M Wheeler-Kingshott, Daniel J Tozer
1NMR Research Unit, Institute of Neurology, University College London, Queen Square, London, UK. k.schmierer@ion.ucl.ac.uk
Magnetic Resonance in Medicine
|January 30, 2008
Summary
Formalin fixation alters quantitative MRI (qMRI) indices in multiple sclerosis (MS) brain tissue. Postfixation T2, T1, and macromolecular proton fraction (f(B)) better predict myelin content than unfixed measures.
Area of Science:
- Neuroimaging
- Pathology
- Histology
Background:
- Quantitative magnetic resonance (qMR) imaging is used to study multiple sclerosis (MS) pathology.
- The impact of formalin fixation on qMR indices in postmortem MS brain tissue is not well understood.
Purpose of the Study:
- To investigate the effects of formalin fixation on various qMR indices in postmortem MS brain tissue.
- To compare the predictive power of unfixed versus fixed qMR indices for myelin content.
Main Methods:
- 15 postmortem MS brain slices were analyzed for T(1), T(2), MTR, f(B), and diffusivity (MD, D(ax), D(rad)) before and after formalin fixation.
- Histological quantification of myelin, axons, and gliosis was performed.
- Statistical analysis included t-tests and regression models.
Main Results:
- Unfixed qMR indices in MS brain tissue were comparable to in vivo patient data.
- Fixation decreased T(1), T(2), and MTR (in NAWM) while increasing f(B).
- Diffusivity measures were lower in unfixed and further reduced after fixation, except for FA. MTR, postfixation T(2), T(1), and f(B) were strong myelin predictors.
Conclusions:
- Formalin fixation significantly alters qMR indices in MS brain tissue.
- Postfixation qMR measures, particularly T(2), T(1), and f(B), are superior predictors of myelin content compared to unfixed measures.
