Use of the Fresnel Transform to detect and correct field drift artefacts in MR images
Chronik B, Alford J
University of Western Ontario
In MR, main field drift during image acquisition causes phase error that in turn produces image artefact. Drift can come from many different sources, but is often associated with heating of resistive elements in the scanner. When the magnetic drift is different in each line of k-space distortions in the phase-encoded direction appear. Averaging images in order to remove this phase error only further degrades the image quality. A new technique is detailed that can identify and remove the unwanted error. This abstract introduces the mathematical transform and shows example images before and after correction.