Echo-planar imaging of porous media with spatial resolution below 100 &mgr;m

A modified version of the echo-planar imaging technique incorporating a Carr-Purcell train of 180 degrees rf pulses (PEPI) has been implemented on a standard spectrometer. It is demonstrated that artifacts in the image due to cumulative errors in the rf field can be reduced by replacing each 180 degrees pulse by a composite sequence of three rf pulses. Artifact-free 3D images at 94 &mgr;m voxel resolution are obtained within 15 min. This technique has been applied to study the drying process in an initially water-saturated model porous medium with characteristic T*2 of order 700 &mgr;s. Copyright 1999 Academic Press.