Meng Gu1, Natalie M. Zahr2,3, Daniel M. Spielman1, Edith V. Sullivan2,3, Adolf Pfefferbaum2,3, Dirk Mayer1,3
1Radiology, Stanford University, Stanford, CA, United States; 2Psychiatry & Behavioral Sciences, Stanford University, Stanford, CA, United States; 3Neuroscience Program, SRI International, Menlo Park, CA, United States
Quantifying and separating glutamate (Glu) and glutamine (Gln) using conventional magnetic resonance spectroscopy on clinical scanners is challenging. Constant-time point-resolved spectroscopy was developed at 3T to detect Glu but does not resolve Gln. To quantify Glu and Gln separately, a time-domain basis set was constructed taking into account T2 relaxation and dephasing from B0 inhomogeneity. Metabolite concentrations were estimated by fitting the basis magnitude spectrum to the measured spectrum. This method was validated using phantoms with different Glu and Gln concentrations. When applied to in vivo data, ethanol-exposed but not control rats showed increased Gln after exposure.