title: Prognostic value of high-field proton magnetic resonance spectroscopy in patients presenting with clinically isolated syndromes suggestive of multiple sclerosis.
abstract: BACKGROUND
  The aim of this study was to determine the prognostic value of metabolic alterations in the normal-appearing white matter (NAWM) of patients presenting with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS) with special regard to the prediction of conversion to definite MS.
  
  
  METHODS
  Using a 3T whole-body MR system, a multisequence conventional MRI protocol and single-voxel proton MR spectroscopy (PRESS, repetition time 2000 ms, echo times 38 ms and 140 ms) of the parietal NAWM were performed in 25 patients presenting with CIS at baseline and in 20 controls. Absolute concentrations of N-acetyl-aspartate (tNAA), myo-inositol (Ins), choline (Cho) and creatine (tCr) as well as metabolite ratios were determined. Follow-up including neurological assessment and conventional MRI was performed 3-4 and 6-7 months after the initial event.
  
  
  RESULTS
  Nine patients converted to definite MS during the follow-up period. Compared to controls, those patients who converted to MS also showed significantly lower tNAA concentrations in the NAWM (-13.4%, P = 0.002) whereas nonconverters (-6.5%, P = 0.052) did not. The Ins concentration was 20.2% higher in the converter group and 1.9% higher in the nonconverter group, but these differences did not reach significance. No significant differences could be observed for tCr and Cho in either patient group.
  
  
  CONCLUSIONS
  Axonal damage at baseline in patients presenting with CIS was more prominent in those who subsequently converted to definite MS in the short term follow-up, indicating that tNAA might be a sufficient prognostic marker for patients with a higher risk of conversion to early definite MS.
authors.affiliation: Department of Radiology/Neuroradiology, University of Bonn, Bonn, Germany. m.wattjes@vumc.nl
authors.forename: Mike P
authors.initials: MP
authors.lastname: Wattjes
authors.forename: Michael
authors.initials: M
authors.lastname: Harzheim
authors.forename: Götz G
authors.initials: GG
authors.lastname: Lutterbey
authors.forename: Manuela
authors.initials: M
authors.lastname: Bogdanow
authors.forename: Stephan
authors.initials: S
authors.lastname: Schmidt
authors.forename: Hans H
authors.initials: HH
authors.lastname: Schild
authors.forename: Frank
authors.initials: F
authors.lastname: Träber
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000378:metabolism; D011379:Prognosis; D011522:Protons; D013577:Syndrome
chemical_list: D011522:Protons