title: ALS surrogate markers. MRS.
abstract: Magnetic resonance spectroscopy (MRS) allows the quantitative assessment of neuronal integrity in vivo based on the resonance intensity of N-acetylaspartate (NAA). A simple approach to quantitation that is commonly used is to quantify the resonance intensity of NAA with respect to creatine (Cr). In patients with ALS, NAA/Cr density is decreased in areas of the brain that contribute significantly to the corticospinal tract. Since MRS is non-invasive, it can be easily used to monitor the evolution of regional changes in NAA/Cr over time. The changes in NAA/Cr over a period of months are small, however, and challenge the precision of the method.
authors.affiliation: Division of Neurology, Department of Medicine, University of Alberta, Canada. sanjay.kalra@ualberta.ca
authors.forename: S
authors.initials: S
authors.lastname: Kalra
authors.forename: D L
authors.initials: DL
authors.lastname: Arnold
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis*; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism*; D003401:Creatine / Q000378:metabolism*; D006801:Humans; D008137:Longitudinal Studies; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009044:Motor Cortex / Q000473:pathology
chemical_list: D015415:Biomarkers; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine