Magnetic field mapping during SSFP using phase-incremented or frequency-shifted magnitude images
AssigneeToshiba America MRI, Inc.
InventorWeiguo Zhang
Life of this patent
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Abstract
A system has been developed for mapping the magnetic field during a balanced steady-state free precession (SSFP) sequence. Field maps are generated by analyzing the magnitude of images acquired using the SSFP imaging sequences with phase increment or frequency shift. The system maps the magnetic field relevant to the imaging sequence and need not rely on phase information. The field maps may be applied to adjust the hardware for correcting the field anomalies contained in the maps. The field maps may also be used for separation of water and fat signals in SSFP imaging.
Claims24
A method for generating maps of magnetic field during a balanced steady-state free precession (SSFP) sequence comprising:
- placing an object to be imaged inside an imaging volume of an MRI scanner;
- applying the balanced SSFP imaging sequence with phase increment or frequency shift to acquire a set of SSFP data in k-space;
- transforming the k-space data into images by performing Fourier transformation of the acquired SSFP data;
- generating magnitude images by determining pixel intensities of the Fourier-transformed SSFP data, and
- generating maps of the magnetic field by analyzing the magnitude images.
A magnetic resonance imaging (MRI) system for generating maps of magnetic field during a balanced steady-state free precession (SSFP) sequence, said system comprising:
- a programmed controller coupled to radio frequency coils and magnetic gradient coils via associated circuits, wherein the controller applies a balanced SSFP imaging sequence with phase increment or frequency shift to acquire a set of SSFP data in k-space, and
- a data processor arithmetically processing the collected SSFP data to produce the field maps, wherein said processor converts the data in k-space to images by performing a Fourier transformation on the acquired SSFP data, and generates the field maps by determining pixel intensities of Fourier transformed SSFP data.
Dependencies are inferred from the claim text.