Geometric distortion correction in gradient-echo imaging by use of dynamictime warping

Distortion caused by local static field Variations in magnetic resonance im aging can be corrected by using a method developed by Chang and Fitzpatrick (CF) that requires two acquisitions identical except for the polarity of t he read gradient, This approach has previously been applied to spin-echo im aging, In this report, its role in correcting geometric distortion in gradi ent-echo imaging is investigated using a dynamic programming algorithm, Thi s approach appears to successfully handle many of the edge artifacts otherw ise inherent in the CF method, Once the correction has been made, it is the n possible to extract the local magnetic field itself, (C) 1999 Wiley-Liss, Inc.