In vivo 31P echo-planar spectroscopic imaging of human calf muscle.
Localized phosphorus-31 NMR spectra of human calf muscle in vivo were obtained by means of echo-planar spectroscopic imaging (EPSI) with a 1.5-T whole-body scanner. The technique permits the measurement of two-dimensional 31P SI data at a minimum acquisition time of 2.4 s (8x8 voxels, TR=300 ms). With 9.4 min measurement time (TR=1100 ms, 64 averages) and 25x25x40 mm spatial resolution in vivo the 31P NMR signal-to-noise ratio (S/N) of the phosphocreatine (PCr) resonance was about 45; the multiplets of nucleoside 5'-triphosphates were resolved. Spectral quality permits quantitative assessment of the PCr signal in a measurement time that is shorter by a factor of 2 or more than the minimum measurement time feasible with chemical-shift imaging. In a functional EPSI study with a time resolution of 20.5 s on the calf muscle of volunteers, spectra showed a 40% decrease of the PCr signal intensity (at rest: S/N congruent with12) upon exertion of the muscle.
Abteilung Biophysik und Medizinische Strahlenphysik, Deutsches Krebsforschungszentrum (dkfz), Heidelberg, D-69120, Germany.
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T
Wilhelm
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Bachert
D017352:Echo-Planar Imaging; D004734:Energy Metabolism / Q000502:physiology*; D005240:Feasibility Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009682:Magnetic Resonance Spectroscopy; D018482:Muscle, Skeletal / Q000502:physiology*; D010725:Phosphocreatine / Q000378:metabolism*; D012016:Reference Values
D010725:Phosphocreatine