Blipped multi gradient‐echo slice excitation profile imaging (bmGESEPI) for fast T 2 * measurements with macroscopic B 0 inhomogeneity compensation

With the rapid development of human MRI at field strengths ≥ 7 T, knowledge of T   2 *relaxation times at such field strengths is needed to optimize acquisition parameters and understand relaxation mechanisms in many applications. However, standard T   2 *measurements (e.g., using conventional multiecho gradient‐echo (GE) sequences) are affected by macroscopic static magnetic field ( B 0 ) inhomogeneities, which are particularly severe at high field strength. The multi‐GE slice excitation profile imaging (mGESEPI) method was developed for T   2 *measurements in the presence of macroscopic B 0 inhomogeneity, but it requires excessive acquisition times at field strengths ≥ 7 T. In this paper a more efficient technique, named blipped mGESEPI (bmGESEPI), is proposed. To demonstrate its advantages, T   2 *maps were acquired using a conventional multiecho GE method, the mGESEPI method, and the bmGESEPI method in postmortem and in vivo human brains at 8 T. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.