Velocity imaging by ex situ NMR

A pulsed field gradient stimulated spin-echo NMR sequence is combined with imaging methods to spatially resolve velocity distributions and to measure 2D velocity maps ex situ. The implementation of these techniques in open sensors provides a powerful non-invasive tool to measure molecular displacement in a large number of applications inaccessible to conventional closed magnets. The method is implemented on an open tomograph that provides 3D spatial localization by combining slice selection in the presence of a uniform static magnetic field gradient along the depth direction with pulsed field gradients along the two lateral directions. Different pipe geometries are used to demonstrate that the sequence performs well even in the extremely inhomogeneous B-0 and B-1 fields of these sensors. (c) 2004 Elsevier Inc. All rights reserved.