A new EPI-based dynamic field mapping method: Application to retrospective geometrical distortion corrections

作者：Lamberton Franck; Delcroix Nicolas; Grenier Denis; Mazoyer Bernard; Joliot Marc^*

来源：Journal of Magnetic Resonance Imaging, 2007, 26(3): 747-755.

DOI：10.1002/jmri.21039

• EPI
• dynamic field mapping
• distortion correction
• phase image
• retrospective correction

Purpose: To restrospectively correct for geometrical distortions, a new dynamic field mapping method suitable for dynamic single-short gradient-echo type echo-planar imaging (GRE-EPI) is proposed.
Materials and Methods: The method requires a single volume additional acquisition and allows the extraction of a field map from each phase volume, assuming invariance across time of the echo time-independent phase component. Performances of the method are assessed using three sets of experiments: the first tests the prerequisite and the modeling; the second tests the method with time-depedent geometrical distortions; and the third presents a comparison with two other methods.
Results: Our results legitimize the modeling procedure and demonstrate that the dynamic method is less sensitive to noise than the other methods. A theoretical explanation for this is proposed in the discussion section.
Conclusion: Given the minor increase in the acquisition time, this method is well suited for functional magnetic resonance imaging; prospective direction.

• 出版日期2007-9
• 单位中国地震局