Relaxation-selective magnetization preparation based on T1 and T2

A magnetization-preparation scheme is described that combines the spin-echo and inversion-recovery (SEIR) to select spins based on both T-1 and T-2 characteristics. The inclusion of T-2 weighting allows for greater relative suppression of some tissues with respect to others, depending on their respective relaxation times, than does inversion-recovery alone. Formulae describing the observed magnetization following SEIR and double-SEIR (DSEIR) are presented with the corresponding formulae for inversion-recovery (IR) and double-IR (DIR). The formulae are validated with experimental studies on MnCl2 solutions and compared numerically for a variety of possible applications. Results indicate that DSEIR may yield 2x or more signal than DIR in some potential applications. (C) 2004 Elsevier Inc. All rights reserved.