Under-sampled 3D MRI using a shells k-space sampling trajectory
First Claim
1. In a method for sampling k-space during a scan with a magnetic resonance imaging (MRI) system that samples k-space as a series of substantially spherical shells of different radius, the improvement comprising:
- a) sampling each shell with a helical spiral sampling trajectory;
b) sampling shells of larger radius with additional helical spiral sampling trajectories that are interleaved with other helical spiral sampling trajectories in the same shell; and
c) undersampling the periphery of k-space by skipping the acquisition of k-space samples in helical spiral sampling trajectories in shells of larger radius.
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Abstract
A 3D MRI image is acquired as a series of spherical shells of increasing radius. Each shell is sampled by one or more interleaved spiral sampling trajectories and to shorten the scan time one or more spiral sampling trajectories are skipped in the larger shells that sample the periphery of k-space. Motion correction of the acquired k-space data is accomplished by reconstructing tracking images from each of the shells and locating markers therein which indicate object movement from a reference position. The k-space data is corrected using this movement information.
46 Citations
12 Claims
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1. In a method for sampling k-space during a scan with a magnetic resonance imaging (MRI) system that samples k-space as a series of substantially spherical shells of different radius, the improvement comprising:
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a) sampling each shell with a helical spiral sampling trajectory;
b) sampling shells of larger radius with additional helical spiral sampling trajectories that are interleaved with other helical spiral sampling trajectories in the same shell; and
c) undersampling the periphery of k-space by skipping the acquisition of k-space samples in helical spiral sampling trajectories in shells of larger radius. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for producing an image of an object with a magnetic resonance imaging (MRI) system, the steps comprising:
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a) acquiring k-space data by performing a series of pulse sequences with the MRI system that sample a series of shells;
b) reconstructing a reference tracking image from k-space data sampled during one or more of the shell trajectories;
c) reconstructing a tracking image from other k-space data sampled during another one or more of the shell trajectories;
d) detecting the movement of the object by comparing the tracking image 10 with the reference tracking image;
e) correcting the k-space data used in step c) for the movement detected in step d) f) repeating steps c), d) and e) until all of the acquired k-space data are corrected for object movement; and
g) reconstructing an image with the corrected k-space data. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification