On doubling the signal in localised stimulated echo measurements

Stimulated echo (STEAM) localisation yields up to 50% of the full magnetisation. It is shown that give the good magnetic field homogeneity now obtained in clinical MRS, and with a slight modification to the gradient pattern, the localised signal may be nearly doubled, although at the expense of introducing a frequency-dependent amplitude for peaks in the final spectrum. A two-step phase cycle is also required. The principle is demonstrated on a clinical MR system, and the relative merits of the sequence are discussed.