Leland Stanford Junior University

John Star-Lack

John Mark Pauly

Daniel Blackburn Vigneron

The present invention uses spectral-spatial 180&deg; refocusing pulses in the point resolved spectroscopy (PRESS) localization sequence. The PRESS sequence uses a series of three pulses having a tilt angle pattern of 90&deg;-180&deg;-180&deg;. The first excitation pulses in the present invention is a spatially selective 90&deg; tilt angle pulse. The following two pulses are spectral-spatial refocusing pulses which provide multi-dimensional selectivity. This feature allows for enhanced solvent suppression, reduced chemical shift induced spatial displacement and an ability to refocus weakly coupled spins. In a preferred embodiment, the spectral-spatial pulses are time-asymmetric and identical, providing for a linear phase profile by means of phase compensation between the two refocusing pulses. Alternatively, a linear phase profile can be provided by using time-symmetric refocusing pulses. The time-asymmetric feature is preferred because it results in lower applied RF power and shorter echo times.

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Palo Alto, CA, United States of America

John Star-Lack