. Author manuscript; available in PMC: 2008 Apr 1.

Published in final edited form as: J Magn Reson. 2006 Dec 22;185(2):204–213. doi: 10.1016/j.jmr.2006.12.010

Table 1.

Outer-Wing Levels of Target Resonances and Spectral Overlap between Target Resonances at Short-Echo and Optimized Sequence Timing Parameters

	Outer-Wing Level¹			Spectral Overlap²
	Gln	Glu	GABA	Gln-Glu		Glu-GABA		Glu→GABA	GABA→Glu
Ratio reference	/Gln	/Glu	/GABA	/Gln	/Glu	/Glu	/GABA	/GABA	/Glu
TE=10ms /TM=10ms	82%	102%	95%	83%	98%	57%	47%	27%	24%
TE=82ms /TM=48ms	9%	5%	8%	1%	1%	3%	3%	3%	0%

The ratio of the peak areas of the outer-wings to those of the respective central peaks was used to evaluate the outer-wing levels of the target resonance of Gln, Glu, and GABA.

Two types of spectral overlap (see Fig. 1) were analyzed: the overlap between the outer-wings of different target resonances, such as the C4 resonances of Gln and Glu, denoted as Gln-Glu, and the overlap between the outer-wing of one target resonance and the central peak of another target resonance, such as the outer-wing of Glu C4 resonance overlapping with the central peak of GABA C2 resonance, denoted as Glu→GABA. For the former (e.g., Gln-Glu), the ratio was taken from the peak area of the overlapped outer-wings of all the involved target resonances to the peak area of the central peak of each involved target resonance; for the latter (e.g., Glu→GABA), the ratio was taken from the peak area of one outer-wing of one target resonance in the overlapped region to the peak area of the central peak of the other target resonance.

In all the ratio calculation, the peak area of central-peak of the target resonance was first chosen as a reference, indicated by /Gln, /Glu, or /GABA. All the results were calculated under the assumption of the same concentrations of Glu, Gln, and GABA as well as the identical relaxtation times.