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Nuclear magnetic resonance of the brain: evaluation of /sup 1/H, /sup 31/P, and /sup 13/C spectra in normal and pathological states in vivo

Thesis/Dissertation ·
OSTI ID:7064701

Spectra of the stable isotopes of hydrogen (/sup 1/H), phosphorus (/sup 31/P), and carbon (/sup 13/C) of brain were acquired at the magnetic field strengths of 1.89 and 8.4 Tesla with specially constructed surface-coil probes. Several physiological variables were monitored simultaneously with nmr data collection; together with the electroencephalogram, the information permitted the evaluation of systemic and cerebral function. The /sup 1/H spectrum of brain, for which no previous information existed, was assigned on the basis of chemical shifts, multiplet structure, homonuclear spin-spin coupling constants, and the known chemical composition of mammalian brain. The assigned resonances were compared in whole brain tissue and acid extracts of animal brains following rapid freezing. Following the intravenous infusion of (1-/sup 13/C)-D-glucose, several resonances were observed in high-resolution /sup 13/C spectra of brain extracts that could be assigned to amino acids and lactate. Employing a similar infusion schedule for (1-/sup 13/C)glucose, the resonances of glucose, glutamate + glutamine, and lactate were detected in hypoxic rabbit brain in vivo. /sup 1/H and /sup 31/P spectroscopy were combined by double-tuning the surface-coil to the resonance frequencies of both nuclei simultaneously, permitting the alternate collection of /sup 1/H and /sup 31/P spectra. Amino acid and lactate metabolism could be assessed simultaneously with high energy phosphates and intracellular pH. This capability was used to probe the relationship between the accumulation and clearance of lactic acid and intracellular pH during hypoxia and recovery in rats.

Research Organization:
Yale Univ., New Haven, CT (USA)
OSTI ID:
7064701
Country of Publication:
United States
Language:
English