Spectrally selective B1-insensitive T2 magnetization preparation sequence

A T2 magnetization‐preparation (T2 Prep) sequence is proposed that is insensitive to B1 field variations and simultaneously provides fat suppression without any further increase in specific absorption rate (SAR). Increased B1 inhomogeneity at higher magnetic field strength (B0 ≥ 3T) necessitates a preparation sequence that is less sensitive to B1 variations. For the proposed technique, T2 weighting in the image is achieved using a segmented B1‐insensitive rotation (BIR‐4) adiabatic pulse by inserting two equally long delays, one after the initial reverse adiabatic half passage (AHP), and the other before the final AHP segment of a BIR‐4 pulse. This sequence yields T2 weighting with both B1 and B0 insensitivity. To simultaneously suppress fat signal (at the cost of B0 insensitivity), the second delay is prolonged so that fat accumulates additional phase due to its chemical shift. Numerical simulations as well as phantom and in vivo image acquisitions were performed to show the efficacy of the proposed technique. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.