Figure 1.

(A) Pulse sequence diagram for the DW-PRESS sequence. Slice-select gradients are shown for each dimension, x (blue), y (red), z (yellow), and diffusion gradients are shown in gray. (B) The maximum achievable b-value as a function of the echo time for the DW-PRESS sequence, which is limited by the maximum achievable diffusion-gradient strengths. The curves were calculated for maximal gradient amplitudes of 40, 80, and 300 mT/m corresponding to the Siemens TRIO, Prisma, and Connectom scanner configurations, respectively. (C) For a given b-value, reduction of the echo time by going from 80 mT/m to 300 mT/m will result in SNR gain. SNR gains were estimated for tNAA, tCho and tCr using their relaxation times T₂ (Ke et al., 2002; Ganji et al., 2012).