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Molar Quantitation of Hepatic Metabolites In Vivo in Proton‐decoupled, Nuclear Overhauser Effect Enhanced 31 P NMR Spectra Localized by Three‐dimensional Chemical Shift Imaging
Author(s) -
Li C. W.,
Negendank W. G.,
MurphyBoesch J.,
PadavicShaller K.,
Brown T. R.
Publication year - 1996
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/(sici)1099-1492(199606)9:4<141::aid-nbm403>3.0.co;2-p
Subject(s) - nuclear magnetic resonance , nuclear overhauser effect , in vivo , proton nmr , chemistry , proton , two dimensional nuclear magnetic resonance spectroscopy , nuclear magnetic resonance spectroscopy , chemical shift , nmr spectra database , spectral line , physics , nuclear physics , biology , microbiology and biotechnology , astronomy
Proton decoupling and nuclear Overhauser effect (NOE) enhancement significantly improve the signal‐to‐noise ratio and enhance resolution of metabolites in in vivo 31 P MRS. We obtained proton‐decoupled, NOE‐enhanced, phospholipid‐saturated 31 P spectra localized to defined regions within the normal liver using three‐dimensional chemical shift imaging. Proton‐decoupling resulted in the resolution of two major peaks in the phosphomonoester (PME) region, three peaks in the phosphodiester (PDE) region and a diphosphodiester peak. In order to obtain molar quantitation, we measured the NOE of all hepatic phosphorus resonances, and we corrected for saturation effects by measuring hepatic metabolite T 1 using the variable nutation angle method with phase‐cycled, B 1 ‐independent rotation, adiabatic pulses. After corrections for saturation effects, NOE enhancement, B 1 variations and point spread effects, the following mean concentrations (mmol/l of liver) (±SD) were obtained: [PME 1 ]=1.2±0.4, [PME 2 +2,3‐DPG]=1.1±0.1, [Pi+2,3‐DPG]=2.8±0.5, [GPEth]=2.8±0.7, [GPChol]=3.5±0.6 and [β‐NTP]=3.8±0.3. T 1 and NOE enhancement were strongly correlated ( r =90), and indicated that the fractional contribution of 1 H‐ 31 P dipolar relaxation to total 31 P relaxation is minimal for NTPs, moderate for PMEs and high for PDEs in liver. Proton‐decoupling and NOE enhancement permit one to obtain more information about in vivo metabolism of liver than previously available and should enhance the utility of 31 P MRS for the study of hepatic disorders.