Magnetization transfer ratio measurement in multiple sclerosis normal-appearing brain tissue: limited differences with controls but relationships with clinical and MR measures of disease

¹ Department of Radiology, MR Center for MS Research, VU University Medical Center, Amsterdam, The Netherlands
² Department of Physics and Medical Technology, MR Center for MS Research, VU University Medical Center, Amsterdam, The Netherlands
³ MR Research Unit and Department of Neurology, Medical University Graz, Graz, Austria
⁴ Department of Clinical Epidemiology and Biostatistics, MR Center for MS Research, VU University Medical Center, Amsterdam, The Netherlands
⁵ Department of Neurology, MR Center for MS Research, VU University Medical Center, Amsterdam, The Netherlands

^* To whom correspondence should be addressed.

	Abstract

We investigated the magnetization transfer ratio (MTR) of normal-appearing white (NAWM) and grey matter (NAGM) in a relatively large group of multiple sclerosis (MS) patients, and the relations of MTR changes with clinical disability. MTR was measured in 66 MS patients (12 PP, 35 RR, 19 SP) and 23 healthy controls, using a whole-brain 3D-FLASH technique corrected post-hoc for B₁-induced variation. Histogram parameters of conservatively selected NAWM and cortical NAGM were analysed using Bonferroni-corrected ANOVA with age as covariate. Additionally, manually outlined regions of interest were analysed using a multilevel method. Lesions had low MTR (mean 22.7±6.9%), but NAWM exhibited limited changes: MTR histogram peak position was 32.8±1.0% in controls and 32.4±0.9% in MS patients, with a significant decrease compared to controls only in SPMS patients (31.9±1.1%, p=0.045). Cortical NAGM histograms did not differ significantly between patients and controls. In SPMS, regional mean MTR was significantly decreased in corpus callosum and hippocampus. MTR histogram parameters of NAGM and NAWM were correlated with EDSS and MSFC scores, with lesion volume and with normalized brain volume. We conclude that disease-induced MTR changes were small in MS NAWM and NAGM, but did correlate with clinical decline, lesion volume and overall cerebral atrophy.

Key Words: B₁ correction, magnetization transfer, multiple sclerosis, normal-appearing brain tissue

First published on March 15, 2007, doi:10.1177/1352458506075521

Multiple Sclerosis 2007;13:708.

A more recent version of this article appeared on July 1, 2007


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