Correlated displacement-T2 MRI by means of a Pulsed Field Gradient-Multi Spin Echo method

A method for correlated displacement-T-2 imaging is presented. A Pulsed Field Gradient-Multi Spin Echo (PFG-MSE) sequence is used to record T-2 resolved propagators on a voxel-by-voxel basis, making it possible to perform single voxel correlated displacement-T-2 analyses. In spatially heterogeneous media the method thus gives access to sub-voxel information about displacement and T-2 relaxation. The sequence is demonstrated using a number of flow conducting model systems: a tube with flowing water of variable intrinsic T-2's, mixing fluids of different T-2's in an X-shaped connector, and an intact living plant. PFG-MSE can be applied to yield information about the relation between flow, pore size and exchange behavior, and can aid volume flow quantification by making it possible to correct for T-2 relaxation during the displacement labeling period Delta in PFG displacement imaging methods. Correlated displacement-T-2 imaging can be of special interest for a number of research subjects, such as the flow of liquids and mixtures of liquids or liquids and solids moving through microscopic conduits of different sizes (e.g., plants, porous media, bioreactors, biomats). (C) 2007 Elsevier Inc. All rights reserved.