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. Author manuscript; available in PMC: 2019 Oct 1.
Published in final edited form as: Magn Reson Med. 2018 Feb 14;80(4):1307–1319. doi: 10.1002/mrm.27142

Figure 1.

Figure 1

(a) Schematic diagram of the GABA-optimized triple-refocusing sequence. The 90° pulse (9.8 ms; BW 4.2 kHz) and the first and third 180° pulses (13.2 ms; BW 1.3 kHz) were slice selective while the second 180° was non-slice selective (NS180; 14 ms long; BW 1.2 kHz). With the four inter-RF pulse time delays (τ1, τ2, τ3, τ4) of (13, 17, 24, 20) ms, the total TE was 74 ms. Slice selective gradients are shown in brown and spoiling gradients in green (each spoiler with strength 16 mT/m and duration 2.8 ms). The 14 ms NS180 pulse was tuned to 4.5 ppm. (b) Numerically calculated triple-refocused spectra of GABA, Glu and Cr are presented at the Cr FWHM of 4 Hz (similar to the in vivo mean singlet linewidth of the present study). The concentration ratio of GABA:Glu:Cr = 1:10:5. A vertical line is drawn at the GABA C2-proton resonance (2.29 ppm).