Systematic Error in the Measurement of [GABA]/[Cr] Ratio Using Methyl Resonance of Creatine

Pallab K. Bhattacharyya¹

While using J-difference editing in GABA measurement, tt is a common practice to report [GABA]/[Cr] ratio by measuring the areas under the 3.01 ppm CH2 (C-4) GABA peak in the edited spectrum and the 3.03 ppm CH3 creatine (Cr) peak in the unedited spectrum. We have shown that this way of measuring [GABA]/[Cr] ratio will introduce a systematic error, and we propose the use of the 3.93 ppm CH2 Cr peak for this purpose. The source of this error is the contribution of 3.01 ppm GABA triplet to the total area under the 3.03 ppm Cr peak