After performing a fast Fourier transform (FFT) along t2, water spectra were evaluated by peak integration. The amount of cerebral spinal fluid (CSF) and tissue water was estimated by fitting a bi-exponential model to the data across the 17 TEs (Mayer et al., 2007). Apodization of the water-suppressed data entailed multiplication with sine-bell functions in both time dimensions and zero-filling up to 4K×1K data points. After performing a 2-dimensional (2D) FFT, effectively decoupled 1D CT-PRESS spectra were obtained by integrating the 2D spectrum in magnitude mode along the frequency domain (f2) within a ±13Hz interval around the spectral diagonal. The 3 singlet resonances (NAA, total creatine (tCr), and Cho) were fit simultaneously, and the glutamate (Glu) resonance fit independently, with a Gaussian function within a ±7.95Hz window using a downhill simplex method (MATLAB). The integrated area under the fitted Gaussian was used for quantification. The quality of the spectra allowed evaluation of signals of the major proton metabolites: NAA (2.01ppm), tCr (3.03ppm and 3.93ppm), Cho (3.20ppm), and Glu (2.35ppm) (Fig. 1).
