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NMR determination of myocardial pH in vivu : Separation of tissue inorganic phosphate from blood 2, 3‐DPG
Author(s) -
Zahler Raphael,
Majumdar S.,
Frederick Blaise,
Laughlin Maren,
Barrett Eugene,
Gore John C.
Publication year - 1991
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.1910170209
Subject(s) - inorganic phosphate , phosphate , nuclear magnetic resonance , chemistry , pulse sequence , pulse (music) , blood flow , phosphate buffered saline , in vivo , chromatography , biochemistry , cardiology , biology , medicine , physics , microbiology and biotechnology , detector , electrical engineering , engineering
Phosphorus NMR can measure myocardial tissue pH from the chemical shift of inorganic phosphate (Pi) in isolated buffer‐perfused hearts, but in vivo the P i peak originating from the myocardium is obscured by the resonance of 2, 3‐diphosphoglycerate (DPG) in the blood, making pH difficult to determine. Taking advantage of the fact that most of the interfering DPG is within the cardiac chambers and is rapidly flowing out of the sensitive volume of our coil, we developed a pulse sequence which would separate myocardial P i signal from interfering DPG. We tested this method on a flow phantom and in living rat heart, using exogenous glycerol phosphate as a blood‐pool marker. The results indicated that signal from moving and nonmoving substances could be separated, and derived values for myocardial pH and PCr/ P i ratio were consistent with previous estimates. This method should be useful for studying myocardial acid‐base physiology with NMR. © 1991 Academic Press, Inc.