THREE-POINT METHOD FOR FAST AND ROBUST FIELD MAPPING FOR EPI GEOMETRIC DISTORTION CORRECTION

Because of its superb temporal resolution, echo planar imaging (EPI) is widely used for functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), and monitoring dynamic processes. EPI suffers from geometric distortions caused by magnetic field inhomogeneities, and although these distortions can be corrected by field mapping, current methods require lengthy auxiliary image acquisitions and/or phase unwrapping. We present a 3-point method for field mapping that circumvents these problems and is robust to additive noise. Results demonstrate that the performance of this approach is markedly better than the standard two-point method and is comparable to methods requiring much longer auxiliary image acquisitions