PARALLEL MRI WITH BO DISTORTION CORRECTION AND MULTI-ECHO DIXON WATER-FAT SEPARATION USING REGULARISED SENSE RECONSTRUCTION

摘要

The invention relates to a method of MR imaging of an object positioned in an examination volume of a MR device (1). The method comprises the steps of: acquiring reference MR signal data from the object (10); deriving a Bo map from the reference MR signal data; adapting sensitivity maps according to the B0 map, which sensitivity maps indicate spatial sensitivity profiles of one or more RF receiving coils (11, 12, 13), to correct for geometric distortions of the sensitivity maps; acquiring imaging MR signal data from the object (10) via the one or more receiving coils (11, 12, 13) with sub-sampling of k-space; and reconstructing a MR image from the imaging MR signal data, wherein sub-sampling artefacts are eliminated using the adapted sensitivity maps. In a preferred embodiment, the reference MR signal data are acquired using a multi-point Dixon technique, wherein a water map and a fat map are derived from the reference MR signal data. A water image and a fat image are reconstructed from the imaging MR signal data using separate water and fat sensitivity maps. The water and fat images are preferably reconstructed using regularised SENSE, wherein a water regularisation map and a fat regularisation map are derived from the multi-point Dixon reference MR signal data. Moreover, the invention relates to a MR device (1) for carrying out the method, and to a computer program to be run on a MR device (1).

主权项

1. A method of magnet resonance (MR) imaging of an object positioned in an examination volume of a MR device, the method comprising the steps of:
acquiring reference MR signal data from the object using a multi-point Dixon technique and by way of two or more RF receiving coils having sensitivity maps that indicate their spatial sensitivity profiles; deriving a B0 map from the reference MR signal data; deriving a multi-point Dixon water map and a multi-point Dixon fat map from the reference MR signal data; correcting the sensitivity maps according to the B0 map, which for geometric distortions of the sensitivity maps; acquiring imaging MR signal data from the object via the one or more receiving coils with sub-sampling of k-space; reconstructing a MR image from the imaging MR signal data, wherein sub-sampling artefacts are eliminated using the corrected sensitivity maps, wherein the correction of the sensitivity maps includes computation of separate corrected sensitivity maps associated with signals from water and from fat, respectively and the reconstruction of the MR image is performed by way of a regularised SENSE reconstruction scheme which employs the corrected sensitivity maps to simultaneously unfold a separate water image and a fat image and the regularisation employs as a regularisation map the multi-point Dixon water map and the multi-point Dixon fat map derived form the reference MR signal data.