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Quantitative magnetic resonance of postmortem multiple sclerosis brain before and after fixation
Author(s) -
Schmierer Klaus,
WheelerKingshott Claudia A.M.,
Tozer Daniel J.,
Boulby Phil A.,
Parkes Harold G.,
Yousry Tarek A.,
Scaravilli Francesco,
Barker Gareth J.,
Tofts Paul S.,
Miller David H.
Publication year - 2008
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.21487
Subject(s) - multiple sclerosis , white matter , fractional anisotropy , gliosis , myelin , nuclear medicine , pathology , fixation (population genetics) , nuclear magnetic resonance , magnetic resonance imaging , medicine , chemistry , central nervous system , population , physics , radiology , environmental health , psychiatry
Unfixed and fixed postmortem multiple sclerosis (MS) brain is being used to probe pathology underlying quantitative MR (qMR) changes. Effects of fixation on qMR indices in MS brain are unknown. In 15 postmortem MS brain slices T 1 , T 2 , MT ratio (MTR), macromolecular proton fraction (f B ), fractional anisotropy (FA), and mean, axial, and radial diffusivity (MD, D ax , and D rad ) were assessed in white matter (WM) lesions (WML) and normal appearing WM (NAWM) before and after fixation in formalin. Myelin content, axonal count, and gliosis were quantified histologically. Student's t ‐test and regression were used for analysis. T 1 , T 2 , MTR, and f B obtained in unfixed MS brain were similar to published values obtained in patients with MS in vivo. Following fixation T 1 , T 2 (NAWM, WML) and MTR (NAWM) dropped, whereas f B (NAWM, WML) increased. Compared to published in vivo data all diffusivity measures were lower in unfixed MS brain, and dropped further following fixation (except for FA). MTR was the best predictor of T myelin (inversely related to myelin) in unfixed MS brain ( r = −0.83; P < 0.01) whereas postfixation T 2 ( r = 0.92; P < 0.01), T 1 ( r = 0.89; P < 0.01), and f B ( r = −0.86; P < 0.01) were superior. All diffusivity measures (except for D ax in unfixed tissue) were predictors of myelin content. Magn Reson Med 59:268–277, 2008. © 2008 Wiley‐Liss, Inc.