title: Integrated data acquisition and processing to determine metabolite contents, relaxation times, and macromolecule baseline in single examinations of individual subjects.
abstract: Absolute quantitation of clinical (1)H-MR spectra is virtually always incomplete for single subjects because the separate determination of spectrum, baseline, and transverse and longitudinal relaxation times in single subjects is prohibitively long. Integrated Processing and Acquisition of Data (IPAD) based on a combined 2-dimensional experimental and fitting strategy is suggested to substantially improve the information content from a given measurement time. A series of localized saturation-recovery spectra was recorded and combined with 2-dimensional prior-knowledge fitting to simultaneously determine metabolite T(1) (from analysis of the saturation-recovery time course), metabolite T(2) (from lineshape analysis based on metabolite and water peak shapes), macromolecular baseline (based on T(1) differences and analysis of the saturation-recovery time course), and metabolite concentrations (using prior knowledge fitting and conventional procedures of absolute standardization). The procedure was tested on metabolite solutions and applied in 25 subjects (15-78 years old). Metabolite content was comparable to previously found values. Interindividual variation was larger than intraindividual variation in repeated spectra for metabolite content as well as for some relaxation times. Relaxation times were different for various metabolite groups. Parts of the interindividual variation could be explained by significant age dependence of relaxation times.
authors.affiliation: Department of Clinical Research, Unit for MR Spectroscopy & Methodology, University of Berne, Switzerland. roland.kreis@insel.ch
authors.forename: Roland
authors.initials: R
authors.lastname: Kreis
authors.forename: Johannes
authors.initials: J
authors.lastname: Slotboom
authors.forename: Lucie
authors.initials: L
authors.lastname: Hofmann
authors.forename: Chris
authors.initials: C
authors.lastname: Boesch
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D001921:Brain / Q000378:metabolism*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000032:analysis / Q000378:metabolism*; D018511:Systems Integration
chemical_list: D009419:Nerve Tissue Proteins; D018377:Neurotransmitter Agents