MRI USING A MODIFIED DIXON SEQUENCE WITH REDUCTION OF FOLD-OVER ARTIFACTS

摘要

A magnetic resonance imaging (MRI) system (500), the system includes at least one controller (510) which performs a modified rotated slab excitation (mROSE) sequence for volume selection to exclude portions of a subject under exam which are within the scanning volume and outside of a field-of-view (FOV) so as to reduce foldover artifacts which originate from the excluded portions of the subject under exam, where the mROSE sequence performs volume excitation based upon either optimized symmetrical, minimum-phase, or stretched minimum-phase radio-frequency (RF) pulses in a sagittal plane and encodes the scanning volume in a coronal plane. The controller also performs a chemical-shift sequence including a modified DIXON (mDIXON) sequence for substantially uniform fat/water separation within a FOV which lies within the scanning volume; and/or acquires echo information for reconstructing at least a part of an image.

主权项

1. A magnetic resonance imaging (MRI) system, the system comprising at least one controller which is configured to:
perform a rotated slab excitation sequence for volume selection to exclude portions of a subject under exam which are within a scanning volume and outside of a field-of-view (FOV) so as to reduce foldover artifacts which originate from the excluded portions of the subject under exam, wherein the rotated slab excitation sequence performs volume excitation in a sagittal plane using radio-frequency (RF) pulses having transition regions with reduced sideband excitation ripples to reduce excitation of the excluded portions of the subject, and encodes the scanning volume in a coronal plane; after performing the rotated slab excitation sequence for the volume selection, perform a chemical-shift sequence comprising a modified DIXON (mDIXON) sequence for fat/water separation within the FOV which lies within the scanning volume; and after performing the chemical-shift sequence for the fat/water separation, acquire echo information of an object within the FOV for reconstructing an image of the object.