Efficient off-resonance correction for spiral imaging

A new spiral imaging technique incorporates the acquisition of a field map into imaging interleaves. Variable density spiral trajectories are designed to oversample the central region of k-space, and interleaves are acquired at two different echo times. A field map is extracted from this data and mu ltifrequency reconstruction is used to form an off-resonance corrected imag e using the entire dataset. Simulation, phantom, and in vivo results indica te that this technique can be used to achieve higher image and/or field map spatial resolution compared to conventional techniques. (C) 2001 Wiley-Lis s, Inc.