title: "Absolute" quantification in magnetic resonance spectroscopy: validation of a clinical protocol in multiple sclerosis.
abstract: MRS allows to measure cerebral metabolites, thus helping to characterize brain disease diagnosis and followup. Metabolite concentration quantification is usually based on metabolite ratio referring to creatine. If this metabolite concentration is supposed to be constant, it may vary in pathological processes. Therefore, "absolute" concentration methodology is needed. The aim of this study is to validate a clinical "absolute" quantification protocol through the development of an external metabolic phantom, calibration and correction, and the investigation of reproducibility issues. When phantom stability was investigated by a short-term and a long-term reproducibility study, both Standard Deviations (SD) were in agreement with literature values. This "absolute" quantification method was applied to patients with Multiple Sclerosis (MS). The results show a significant decrease in both N-Acetyl Aspartate (NAA) and choline concentrations.
authors.affiliation: CREATIS-LRMN, CNRS UMR 5220 & Inserm U630, Université de Lyon, 69621 Villeurbanne, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Bagory
authors.forename: Françoise
authors.initials: F
authors.lastname: Durand-Dubief
authors.forename: Danielle
authors.initials: D
authors.lastname: Ibarrola
authors.forename: Christian
authors.initials: C
authors.lastname: Confavreux
authors.forename: Dominique
authors.initials: D
authors.lastname: Sappey-Marinier
mesh_terms: D000328:Adult; D000465:Algorithms; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D001921:Brain / Q000378:metabolism*; D002794:Choline / Q000032:analysis*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000378:metabolism*; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D001224:Aspartic Acid; C000179:N-acetylaspartate; D002794:Choline