Namkug Kim1, Young-Hoon Sung1, Nivedita Agarwal1, Eric Jensen2, In Kyoon Lyoo3, Brent P. Forester2, Perry F. Renshaw1
1The Brain Institute, University of Utah, Salt Lake City, UT, United States; 2Department of Psychiatry, Harvard Medical School, Belmont, MA, United States; 3Department of Psychiatry, Seoul National University, Seoul, Korea, Republic of
It is typically difficult to differentiate NAAG directly from NAA of standard MRS due to the low concentration of NAAG and overlap with other metabolites. Five repetitive scan trials of five phantom cases in which all the phantoms were scanned using CSI at one-day intervals to figure out the reproducibility and the accuracy of the measurement. The phantom cases contained a range of concentrations of Glu, NAAG, and constant concentrations of other ten metabolites. It was found that as the concentration of NAAG becomes smaller (especially below 1mmol/kg), the overestimation bias in measuring the NAAG gets stronger.