title: Reproducibility over a 1-month period of 1H-MR spectroscopic imaging NAA/Cr ratios in clinically stable multiple sclerosis patients.
abstract: N-acetylaspartate/creatine (NAA/Cr) ratios, assessed with proton magnetic resonance spectroscopy, are increasingly used as a surrogate marker for axonal dysfunction and degeneration in multiple sclerosis (MS). The purpose of this study was to test short-time reproducibility of NAA/Cr ratios in patients with clinically stable MS. In 35 MS patients we analysed NAA/Cr ratios obtained with (1)H-MR spectroscopic imaging at the centrum semiovale either with lateral ventricles partially included (group 1; n=15) or more cranially with no ventricles included (group 2; n=20). To test short-term reproducibility of the NAA/Cr measurements, patients were scanned twice 4 weeks apart. We determined mean NAA/Cr and Cho/Cr ratios of 12 grey matter and 24 white matter voxels. Mean NAA/Cr ratios of both the white and grey matter did not change after 4 weeks. Overall 4-week reproducibility of the NAA/Cr ratio, expressed as coefficient of variation, was 4.8% for grey matter and 3.5% for white matter. Reproducibility of cranial scanning of the ventricles was slightly better than with cerebrospinal fluid included. Our study shows good short-term reproducibility of NAA/Cr ratio measurements in the centrum semiovale, which supports the reliability of this technique for longitudinal studies.
authors.affiliation: Department of Neurology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9713, GZ, Groningen, The Netherlands. j.p.mostert@neuro.umcg.nl
authors.forename: J P
authors.initials: JP
authors.lastname: Mostert
authors.forename: Y
authors.initials: Y
authors.lastname: Blaauw
authors.forename: M W
authors.initials: MW
authors.lastname: Koch
authors.forename: A J
authors.initials: AJ
authors.lastname: Kuiper
authors.forename: J M
authors.initials: JM
authors.lastname: Hoogduin
authors.forename: J
authors.initials: J
authors.lastname: De Keyser
mesh_terms: D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D003404:Creatinine / Q000032:analysis*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000378:metabolism*; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D011522:Protons; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003404:Creatinine