Reduced NAA-levels in the NAWM of patients with MS is a feature of progression. A study with quantitative magnetic resonance spectroscopy at 3 Tesla.

Fahmy Aboul-Enein,Romana Höftberger,Daniela Prayer,Wolfgang Kristoferitsch,Martin Krššák,Juri G Gelovani

doi:10.1371/journal.pone.0011625

Fahmy Aboul-Enein, Romana Höftberger + Show 4 more

Open Access

https://doi.org/10.1371/journal.pone.0011625

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Journal: PloS one	Publication Date: Jul 20, 2010
Citations: 106	License type: CC BY 4.0

Affiliation: Donauspital, Medical University of Vienna

Abstract

BackgroundReduced N-acetyl-aspartate (NAA) levels in magnetic resonance spectroscopy (MRS) may visualize axonal damage even in the normal appearing white matter (NAWM). Demyelination and axonal degeneration are a hallmark in multiple sclerosis (MS).ObjectiveTo define the extent of axonal degeneration in the NAWM in the remote from focal lesions in patients with relapsing-remitting (RRMS) and secondary progressive MS (SPMS).Material and Methods37 patients with clinical definite MS (27 with RRMS, 10 with SPMS) and 8 controls were included. We used 2D 1H-MR-chemical shift imaging (TR = 1500ms, TE = 135ms, nominal resolution 1ccm) operating at 3Tesla to assess the metabolic pattern in the fronto–parietal NAWM. Ratios of NAA to creatine (Cr) and choline (Cho) and absolute concentrations of the metabolites in the NAWM were measured in each voxel matching exclusively white matter on the anatomical T2 weighted MR images.ResultsNo significant difference of absolute concentrations for NAA, Cr and Cho or metabolite ratios were found between RRMS and controls. In SPMS, the NAA/Cr ratio and absolute concentrations for NAA and Cr were significantly reduced compared to RRMS and to controls.ConclusionsIn our study SPMS patients, but not RRMS patients were characterized by low NAA levels. Reduced NAA-levels in the NAWM of patients with MS is a feature of progression.

Highlights

multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) of unknown origin causing demyelination and axonal degeneration [1]
In SPMS, the NAA/Cr ratio and absolute concentrations for NAA and Cr were significantly reduced compared to relapsing-remitting course (RRMS) and to controls
In our study SPMS patients, but not RRMS patients were characterized by low NAA levels

Summary

Introduction

MS is a chronic inflammatory disease of the central nervous system (CNS) of unknown origin causing demyelination and axonal degeneration [1]. Even in very early stages of RRMS a ‘‘clinical silent’’ focal or diffuse ‘‘background inflammation’’ not detectable in conventional MRI may progress and cause diffuse axonal damage. This subtle axonal degeneration may be visualized by magnetic resonance spectroscopy (1H-MRS) as reduction of N-acetyl-aspartate (NAA) levels [9,10,11,12,13,14]. These results are, controversially discussed, due to new insights from the recently improved 1H-MRS technique. Demyelination and axonal degeneration are a hallmark in multiple sclerosis (MS)

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Conclusion