title: Assessment of absolute metabolite concentrations in human tissue by 31P MRS in vivo. Part II: Muscle, liver, kidney.
abstract: Absolute metabolite concentrations were assessed in the muscle, the liver, and the kidney of healthy human volunteers by 31P MRS. Fully relaxed in vivo spectra were acquired with a surface coil and were localized with an adiabatic ISIS pulse sequence. The spectra were quantified with a subsequent measurement of a calibration phantom and were processed iteratively in the time domain. The following mean metabolite concentrations (mmol/liter) were measured in the resting male calf muscle (n = 9), in the fasting liver (n = 12), and in the orthotopic kidney (n = 5): [PME] = 2.0 +/- 0.6, 3.8 +/- 0.7, and 2.6 +/- 0.9, [Pi] = 2.9 +/- 0.3, 1.8 +/- 0.3, and 1.6 +/- 0.4, [PDE] = 3.8 +/- 0.8, 9.7 +/- 1.5, and 4.9 +/- 1.1, [PCr] = 22.0 +/- 1.2, 0, and 0, [NTP] = 5.7 +/- 0.4, 2.9 +/- 0.4, and 2.0 +/- 0.3, respectively. Several interesting findings are to be emphasized: The concentrations of Pi, PCr, and NTP were 20% lower in the muscle of women than of men. In addition, the pHi was significantly lower in female muscle (6.99 +/- 0.03) than in male muscle (7.05 +/- 0.03). The pHi in the liver (7.12 +/- 0.09) and in the kidney (7.09 +/- 0.08) were higher than in the muscle of both genders. The free magnesium concentration (mmol/liter) was higher in the liver (1.40 +/- 0.64) than in the kidney (0.79 +/- 0.39) and in the muscle (0.52 +/- 0.10).
authors.affiliation: Institute of Biomedical Engineering and Medical Informatics, University of Zurich, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Buchli
authors.forename: D
authors.initials: D
authors.lastname: Meier
authors.forename: E
authors.initials: E
authors.lastname: Martin
authors.forename: P
authors.initials: P
authors.lastname: Boesiger
mesh_terms: D000328:Adult; D002138:Calibration; D005260:Female; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008961:Models, Structural; D018482:Muscle, Skeletal / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D012737:Sex Factors
chemical_list: D010758:Phosphorus