Method of oscillogram filtering for radial MRI data
A system includes a data receiver, a sinogram generator, a processor, a filter module, and an output module. The data receiver is configured to receive radial ordered magnetic resonance data. The sinogram generator is configured to generate a first sinogram corresponding to a view angle as a function of a readout direction for the magnetic resonance data. The processor is configured to generate an oscillogram having an angular frequency axis. The oscillogram corresponds to a Fourier transform of the first sinogram. The filter module is configured to selectively filter a peak in a projection formed along a selected axis of the oscillogram, the peak being related to an interference signal such as an RF interference. The selected axis is orthogonal to the angular frequency axis. The output module is configured to form a second sinogram corresponding to a transform of the filtered projection.
1. A system comprising:
a data receiver configured to receive radial ordered magnetic resonance data, the data including an artifact and the data including phase information and frequency information;
a sinogram generator configured to generate a first sinogram corresponding to a view angle as a function of a readout direction for the magnetic resonance data;
a processor configured to generate an oscillogram having an angular frequency axis and a time axis that is orthogonal to the angular frequency axis, the oscillogram corresponding to a transform of the first sinogram;
a filter module configured to selectively filter, using a peak detection algorithm to detect peaks corresponding to zipper artifacts, a projection formed along the time axis of the oscillogram that is orthogonal to the angular frequency axis; and
an output module configured to form a second sinogram corresponding to a transform of the filtered projection and to generate an image using the second sinogram, the image having the artifact removed or suppressed.
2. The system of claim 1 wherein the data receiver is configured to receive spherical ordered data.
3. The system of claim 1 wherein the data receiver is configured to receive at least one of 2D data or 3D data.
4. The system of claim 1 wherein the processor is configured to implement at least one of a Fourier transform or an inverse Fourier transform.
5. The system of claim 1 wherein the processor is configured to implement a Fourier transform along the view angle and along the readout direction.
6. The system of claim 1 wherein the filter module is configured to form the projection by integrating magnitude components of the oscillogram.
7. The system of claim 5 wherein the filter module is configured to form a 1D projection in a direction aligned with a fast axis of the oscillogram, wherein the fast axis of the oscillogram corresponds to the Fourier transform along the readout direction of the first sinogram.
8. The system of claim 1 wherein the filter module is configured to implement at least one of a notch filter and a mask filter.
9. The system of claim 1 wherein the filter module is configured to implement a median filter.
10. The system of claim 1 wherein the filter module includes implementing a peak detector.
11. A method comprising:
receiving a first sinogram corresponding to radial ordered magnetic resonance data, the data including an artifact and the data including phase information and frequency information, the first sinogram representing a view angle as a function of a readout direction for the magnetic resonance data;
using a processor to transform the first sinogram to form an oscillogram having an angular frequency axis and a time axis that is orthogonal to the angular frequency axis;
forming a projection along the time axis of the oscillogram that is orthogonal to the angular frequency axis;
filtering a peak in the projection sing a peak detection algorithm to detect peaks corresponding to zipper artifacts;
transforming the filtered projection to form a second sinogram; and
generating an image using the second sinogram, the image having the artifact removed or suppressed.
12. The method of claim 11 wherein receiving the first sinogram corresponding to radial ordered magnetic resonance data includes receiving spherical ordered data.
13. The method of claim 11 wherein receiving the first sinogram corresponding to radial ordered magnetic resonance data includes receiving at least one of 2D data or 3D data.
14. The method of claim 11 wherein using the processor to transform includes executing at least one of a Fourier transform or an inverse Fourier transform.
15. The method of claim 11 wherein using the processor to transform the first sinogram to form an oscillogram includes executing a Fourier transform along the view angle and executing a Fourier transform along the readout direction.
16. The method of claim 11 wherein forming the projection includes forming the projection by integrating magnitude components of the oscillogram.
17. The method of claim 15 wherein forming the projection along the axis of the oscillogram includes forming a 1D projection in a direction aligned with a fast axis of the oscillogram, wherein the fast axis of the oscillogram corresponds to the Fourier transform along the readout direction of the first sinogram.
18. The method of claim 11 wherein filtering includes at least one of notch filtering or mask filtering.
19. The method of claim 11 wherein filtering includes implementing a median filter algorithm.
20. The method of claim 11 wherein filtering includes implementing a peak detection algorithm.