Abstract Details

Title Localisation of Grey Matter Atrophy and Magnetisation Transfer Ratio Abnormalities in Multiple Sclerosis Subgroups

Topic MS and Related Diseases

Presentation(s) (-)

Poster/Presentation
Number 005

Objective

Background In multiple sclerosis (MS), brain GM atrophy may reflect neuronal loss and reduced magnetisation transfer ratio (MTR) reflect demyelination.

Design/Methods 102 patients (51 RRMS, 30 SPMS, 21 PPMS) and 32 controls had T1-weighted (T1w) volumetric and magnetisation transfer scans, acquired at 1x1x1mm3. MTR maps were calculated using MT on and off sequences. T1w scans were segmented into GM, white matter and CSF. For the MTR analyses, the resulting tissue classes were binarised using a maximum likelihood algorithm with a conservative 90% threshold, reducing the possibility of partial volume effects. Using SPM8, T1w scans were non-linearly registered to create a DARTEL template, registered to MNI space using affine transformation, and smoothed with an 8mm full-width half maximum Gaussian kernel. Voxel-based morphometry (VBM) was used to compare regional differences in GM atrophy and MTR, in MS patient subgroups versus controls, adjusting for age and gender, using family wise error (FWE) correction at p<0.05.

Results Compared with controls, PPMS and SPMS groups exhibited more areas of MTR reduction than atrophy while RRMS subjects showed more areas of atrophy than reduced MTR. Co-localisation of atrophy and reduced MTR was most evident in RRMS and SPMS in the deep GM and in PPMS in cortical GM.

Conclusions Assuming that reduced GM MTR implies demyelination and atrophy reflects neuronal loss, the results suggest that: (i) in progressive (SP and PP) MS there is overall more extensive GM demyelination than neuronal loss; (ii) in RRMS there is overall more extensive GM neuronal loss with less noticeable demyelination, and (iii) co-existent demyelination and neuronal loss is most evident in deep GM in relapse onset (RR and SP) MS and in cortical GM in PPMS.

Authors/Disclosures
PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
Daniel O. Claassen, MD, FAAN (Vanderbilt University Medical Center)	Dr. Claassen has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Spark . The institution of Dr. Claassen has received personal compensation in the range of $50,000-$99,999 for serving as a Consultant for Alterity. Dr. Claassen has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for University of Michigan. Dr. Claassen has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for HD Insights. The institution of Dr. Claassen has received research support from NIH. The institution of Dr. Claassen has received research support from CHDI. The institution of Dr. Claassen has received research support from HDSA. The institution of Dr. Claassen has received research support from Department of Defense. The institution of Dr. Claassen has received research support from CHDI. The institution of Dr. Claassen has received research support from Genentech/ Roche.
	No disclosure on file
David H. Miller, MD, MBChB, FRCP (Univ Dept of Clinical Neuro)	No disclosure on file
Declan T. Chard	No disclosure on file

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