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Quantitative proton spectroscopy of canine brain: in Vivo and in Vitro correlations
Author(s) -
Barker Peter B.,
Breiter Steven N.,
Soher Brian J.,
Chatham John C.,
Forder John R.,
Samphilipo Michael A.,
Magee Carolyn A.,
Anderson James H.
Publication year - 1994
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910320202
Subject(s) - phosphocreatine , in vivo , chemistry , phosphocholine , metabolite , creatine , nuclear magnetic resonance , nuclear magnetic resonance spectroscopy , perchloric acid , proton nmr , spectroscopy , analytical chemistry (journal) , chromatography , biochemistry , phospholipid , phosphatidylcholine , stereochemistry , biology , endocrinology , physics , microbiology and biotechnology , organic chemistry , membrane , energy metabolism , quantum mechanics
Quantitative, single‐voxel proton NMR spectroscopy of normal brain was performed in five adult beagle dogs using the cerebral water signal as an internal intensity reference. The same brain regions were then rapidly isolated and frozen using a pneumatic biopsy drill, perchloric acid extracted, and analyzed by biochemical assay and high‐resolution NMR spectroscopy. The concentrations of the major resonances in the in vivo and in vitro spectra were compared, and good agreement was found between the different measurements. The in vivo spectra contained three peaks at 3.21, 3.04, and 2.02 ppm, which are usually assigned to trimethylamines (TMA), creatines, and N ‐acetyl derivatives (NAc), which corresponded to be the following metabolite concentration values: 1.7 ± 0.6, 7.7 ± 2.1, and 10.9 ± 2.7 μmol/g wet weight respectively. In vitro , the following metabolite concentrations were measured: glycerophosphocholine (GPC) 1.3 ± 0.2, phosphocholine (PC) 0.5 ± 0.1, phosphocreatine (PCr) 2.6 ± 0.4, creatine (Cr) 5.9 ± 1.4, and N‐Acetyl aspartate (NAA) 8.9 ± 1.8 μmol/g wet weight. Therefore, the 3.21 ppm resonance observed in the in vivo spectrum is predominantly GPC and PC in a ratio of 2.6:1, the 3.04 ppm resonance is Cr and PCr in a ratio of 2.3:1, and the 2.02 ppm resonance is predominantly (≈80%) NAA with small contributions from N ‐acetylaspartyl‐glutamate (NAAG) and glutamate. The data presented here validate the technique of water referencing as a simple and convenient means of quantitating single‐voxel in vivo proton NMR spectra of the brain.