Reduction of motion artifact in NMR images using spherical navigator signals
AssigneeMayo Foundation for Medical Education and Research
InventorsClifford R. Jack, Armando Manduca, Roger Grimm, Edward B. Welch
Life of this patent
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Abstract
A series of fMRI image frames are acquired along with interleaved navigator signals. The navigator signals are acquired while three orthogonal readout gradients are applied such that a spherical surface is sampled in k-space. The navigator signals are analyzed to measure subject rotational and translational motion during the scan.
Claims14
A method for detecting movement of a subject during a scan in which NMR image data is acquired with a magnetic resonance imaging system, the steps comprising:
- a) acquiring the NMR image data using a series of NMR imaging pulse sequences;
- b) interleaving with the series of NMR imaging pulse sequences a series of NMR navigator signal pulse sequences, each navigator signal pulse sequence including the application of three orthogonal magnetic field gradients during the readout of its NMR navigator signal such that a resulting NMR navigator signal samples a three-dimensional surface in k-space;
- c) acquiring the NMR navigator signals during the scan;
- and
- d) analyzing the acquired NMR navigator signals to measure rotational and translational motion of the subject during the scan;
- e) calculating corrective values from the measured subject rotation and subject translation;
- and
- f) correcting NMR image data using the corrective values.
A method for acquiring fMRI data from a subject with a magnetic resonance imaging (MRI) system, the steps comprising:
- a) acquiring NMR image data by performing a series of NMR imaging pulse sequences with the MRI system;
- b) forming the acquired NMR image data into a series of data sets from which a corresponding series of images may be reconstructed;
- c) interleaving with the series of NMR imaging pulse sequences a series NMR navigator signal pulse sequences, each navigator signal pulse sequence being associated with a data set and including the application of three orthogonal magnetic field gradients during the readout of its NMR navigator signal such that a resulting NMR navigator signal samples a portion of a substantially three-dimensional spherical surface in k-space;
- d) acquiring each NMR navigator signal and with respect to each:
- i) analyzing the NMR navigator signal to measure motion of the subject;
- ii) calculating corrective values from the measured subject motion;
- and
- iii) correcting the NMR image data in its associated data set using the corrective values.
Dependencies are inferred from the claim text.