Figure 1.

Quantification of ethanol MRS signal intensity in GM and WM. (A) Overlay of the 8×8 grid of (8 mm)³ CSI voxels n an axial T₁-weighted image. The region outlined in red is the PRESS-selected volume, within which ethanol and H₂O resonances were quantified. (B) Example spectra acquired prior to (black trace) and following (red trace) intravenous infusion of ethanol. The ethanol methyl ¹H signal is determined from the difference spectrum (lower trace). (C) Observed (abscissa) vs. expected (ordinate) ${\text{S}}_{\text{i},\text{j}}^{\text{EtOH}}(150\text{ ms})/{\text{S}}_{\text{i},\text{j}}^{{\text{H}}_2\text{O}}(0)$ values obtained for the 995 voxels quantified, after using Eqs. [7]–[9] to estimate $\frac{[\text{EtOH}]}{[{\text{H}}_2\text{O}]}{\mathrm{\beta }}_{\text{j}}^{\text{GM}}$ and $\frac{[\text{EtOH}]}{[{\text{H}}_2\text{O}]}{\mathrm{\beta }}_{\text{j}}^{\text{WM}}$ for each monkey at each of the four time points. Data values are color-coded according to the experimental time point in which they were acquired.