title: Technical and experimental features of Magnetic Resonance Spectroscopy of brain glycogen metabolism.
abstract: In the brain, glycogen is a source of glucose not only in emergency situations but also during normal brain activity. Altered brain glycogen metabolism is associated with energetic dysregulation in pathological conditions, such as diabetes or epilepsy. Both in humans and animals, brain glycogen levels have been assessed non-invasively by Carbon-13 Magnetic Resonance Spectroscopy (13C-MRS) in vivo. With this approach, glycogen synthesis and degradation may be followed in real time, thereby providing valuable insights into brain glycogen dynamics. However, compared to the liver and muscle, where glycogen is abundant, the sensitivity for detection of brain glycogen by13C-MRS is inherently low. In this review we focus on strategies used to optimize the sensitivity for13C-MRS detection of glycogen. Namely, we explore several technical perspectives, such as magnetic field strength, field homogeneity, coil design, decoupling, and localization methods. Furthermore, we also address basic principles underlying the use of13C-labeled precursors to enhance the detectable glycogen signal, emphasizing specific experimental aspects relevant for obtaining kinetic information on brain glycogen.
authors.affiliation: Laboratory for Functional and Metabolic Imaging (LIFMET), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
authors.forename: Ana Francisca
authors.initials: AF
authors.lastname: Soares
authors.affiliation: Laboratory for Functional and Metabolic Imaging (LIFMET), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Department of Radiology, University of Genève (UNIGE), Switzerland; Center for Biomedical Imaging (CIBM), Lausanne, Switzerland; Department of Radiology, University of Lausanne (UNIL), Switzerland.
authors.forename: Rolf
authors.initials: R
authors.lastname: Gruetter
authors.affiliation: Department of Radiology, University of Genève (UNIGE), Switzerland; Center for Biomedical Imaging (CIBM), Lausanne, Switzerland. Electronic address: hongxia.lei@epfl.ch.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Lei
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002247:Carbon Isotopes / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008954:Models, Biological
chemical_list: D002247:Carbon Isotopes; D006003:Glycogen