Saving transverse magnetization

A magnetization storage sequence, ALT-1 (alternating longitudinal and transverse components), is reported. The ALT-1 sequence is a hybrid of two types of storage sequences, the Carr-Purcell type and store-and-restore sequences. During incremental storage periods within the ALT-1 sequence, essentially half of the initially transverse magnetization is stored along the z-axis and the other half is prolonged by an echo-generating pulse. The portions of initial magnetization that are stored as longitudinal components or transverse components are alternated by a pi/2 pulse during the cycle. Both transverse components of the initial magnetization are treated the same in the ALT-1 sequence and orientational (phase) information of the initial magnetization is kept during the storage period. The ALTA sequence can preserve magnetization more effectively than a published class of modified Carr-Purcell type sequences, because essentially half of the magnetization during incremental storage periods is not subjected to relaxation from T-2 effects. (C) 2009 Elsevier Inc. All rights reserved.