MRI acquisition using sense and highly undersampled fourier space sampling
View Patent ↗An MRI system produces a three-dimensional image by acquiring NMR signals that fully sample a central region of k-space and partially sample peripheral region of k-space. Specifically, k-space is arranged as a three-dimensional (3D) Cartesian grid of points that is divided into a central region of k-space and a peripheral region of k-space. Points are selected in k-space within a plurality of radial vanes that extend radially outward from the central region of k-space through the peripheral region of k-space as viewed in a plane sampled by two phase encoding gradients to create a plurality of gaps between the radial vanes that is substantially a factor of N times greater in area than the radial vanes. Using an MRI system having arrays of RF receiver coils, NMR signals are acquired from a subject to fully sample the central region of the 3D k-space and undersample the peripheral region of k-space by only sampling k-space within the plurality of radial vanes. An image of the subject is reconstructed using the acquired NMR signals.
1. A method for producing an image with a magnetic resonance imaging (MRI) system, the steps comprising:
a) arranging a three-dimensional (3D) k-space along a Cartesian grid of points;
b) dividing k-space into a central region of k-space and a peripheral region of k-space;
c) selecting points in k-space within a plurality of radial vanes that extend radially outward from the central region of k-space through the peripheral region of k-space as viewed in a plane sampled by two phase encoding gradients to create a plurality of gaps between the radial vanes that is substantially a factor of N times greater in area than the radial vanes;
d) acquiring, with an MRI system having arrays of RF receiver coils, NMR signals from a subject to fully sample the central region of the 3D k-space and undersample the peripheral region of k-space by only sampling k-space within the plurality of radial vanes; and
e) reconstructing an imaging of the subject using the acquired NMR signals.
2. The method of claim 1 wherein the radial vanes distributed substantially evenly around the central region of k-space.
3. The method of claim 1 wherein step e) further includes employing a homodyne image reconstruction process.
4. The method of claim 1 wherein the radial vanes are asymmetrical.
5. The method of claim 1 wherein step e) includes employing image a Fast Fourier Transform to reconstruct the image of the subject.
6. The method of claim 1 wherein the factor of N equals four.
7. The method of claim 1 wherein step e) includes weighting data in the annular vanes by the factor of N.
8. The method of claim 1 further comprising repeating steps a) through e) to generate a time series of 3D image data sets.
9. The method of claim 8 wherein a position of the radial vanes are adjusted between each of the time series of 3D image data sets.
10. The method of claim 9 wherein step e) includes combining data from consecutive image data sets in the time series of 3D image data sets.