Figure 1:

A, Pulse sequence schematic for measurement of ¹H cross-relaxation in downfield MRS. First, the magnetization is inverted using a spectrally selective (not shown) or broadband inversion pulse (shown). A spectrally selective uniform phase excitation pulse is followed by a spin echo localization using three spatially-selective refocusing pulses. B, Schematic showing the spectrally-selective inversion (scan 1) and broadband inversion recovery (scan 2) experiments. MRS data from both experiments is used to determine T₁ and cross-relaxation rates of observed resonances.