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In vivo 31 P magnetic resonance spectroscopy of the human liver at 7 T: an initial experience
Author(s) -
Chmelik Marek,
Považan Michal,
Krššák Martin,
Gruber Stephan,
Tkačov Martin,
Trattnig Siegfried,
Bogner Wolfgang
Publication year - 2014
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/nbm.3084
Subject(s) - phosphorylcholine , chemistry , nuclear magnetic resonance , nuclear magnetic resonance spectroscopy , in vivo , phosphocholine , analytical chemistry (journal) , phosphatidylcholine , biochemistry , phospholipid , chromatography , biology , stereochemistry , physics , microbiology and biotechnology , membrane
Phosphorus ( 31 P) MRS is a powerful tool for the non‐invasive investigation of human liver metabolism. Four in vivo 31 P localization approaches (single voxel image selected in vivo spectroscopy (3D‐ISIS), slab selective 1D‐ISIS, 2D chemical shift imaging (CSI), and 3D‐CSI) with different voxel volumes and acquisition times were demonstrated in nine healthy volunteers. Localization techniques provided comparable signal‐to‐noise ratios normalized for voxel volume and acquisition time differences, Cramer–Rao lower bounds (8.7 ± 3.3% 1D‐ISIS , 7.6 ± 2.5% 3D‐ISIS , 8.6 ± 4.2% 2D‐CSI , 10.3 ± 2.7% 3D‐CSI ), and linewidths (50 ± 24 Hz 1D‐ISIS , 34 ± 10 Hz 3D‐ISIS , 33 ± 10 Hz 2D‐CSI , 34 ± 11 Hz 3D‐CSI ). Longitudinal ( T 1 ) relaxation times of human liver metabolites at 7 T were assessed by 1D‐ISIS inversion recovery in the same volunteers ( n = 9). T 1 relaxation times of hepatic 31 P metabolites at 7 T were the following: phosphorylethanolamine – 4.41 ± 1.55 s; phosphorylcholine – 3.74 ± 1.31 s; inorganic phosphate – 0.70 ± 0.33 s; glycerol 3‐phosphorylethanolamine – 6.19 ± 0.91 s; glycerol 3‐phosphorylcholine – 5.94 ± 0.73 s; γ‐adenosine triphosphate (ATP) – 0.50 ± 0.08 s; α‐ATP – 0.46 ± 0.07 s; β‐ATP – 0.56 ± 0.07 s. The improved spectral resolution at 7 T enabled separation of resonances in the phosphomonoester and phosphodiester spectral region as well as nicotinamide adenine dinucleotide and uridine diphosphoglucose signals. An additional resonance at 2.06 ppm previously assigned to phosphoenolpyruvate or phosphatidylcholine is also detectable. These are the first 31 P metabolite relaxation time measurements at 7 T in human liver, and they will help in the exploration of new, exciting questions in metabolic research with 7 T MR. Copyright © 2014 John Wiley & Sons, Ltd.