Systems and methods for artifact removal for computed tomography imaging

1. An imaging system comprising:

a computed tomography (CT) acquisition unit comprising an X-ray source and a CT detector configured to collect CT imaging data of an object to be imaged, the X-ray source and CT detector configured to be rotated relative to the object to be imaged and to collect a series of projections of the object as the X-ray source and CT detector rotate relative the object to be imaged; and

at least one processor operably coupled to the CT acquisition unit, the at least one processor configured to:

reconstruct an initial image using the CT imaging information, the initial image including at least one object representation portion and at least one artifact portion;

identify at least one region of the initial image containing at least one artifact, and isolate the at least one artifact from desired image content by analyzing the initial image using an artifact dictionary and a non-artifact dictionary, the artifact dictionary including entries describing corresponding artifact image portions, the non-artifact dictionary including entries defining corresponding non-artifact image portions, wherein the non-artifact dictionary includes entries corresponding to true or accurate representations of anatomy and entries corresponding to random or uniformly distributed noise; and

remove the at least one artifact from the initial image to provide a corrected image.

2. The imaging system of claim 1 , wherein the at least one processor is configured to identify the at least one artifact using a weighted combination of an entry from the artifact dictionary and an entry from the non-artifact dictionary.

3. The imaging system of claim 1 , wherein the at least one processor is configured to:

divide the initial image into plural patches;

subtract a mean value of at least one patch from the at least one patch; and

analyze the at least one patch using the artifact dictionary and non-artifact dictionary after subtracting the mean value from the at least one patch.

4. The imaging system of claim 1 , wherein the at least one processor is configured to:

divide the initial image into plural patches;

analyze at least one patch separately from at least some of the other patches, wherein the artifact dictionary entries and the non-artifact dictionary entries correspond to a patch size of the plural patches, to identify at least one artifact in the at least one patch;

remove the at least one artifact from the at least one patch to generate at least one corrected patch; and

combine the at least one corrected patch with additional patches to provide the corrected image.

5. The imaging system of claim 4 , wherein the at least one processor is configured to select non-artifact dictionary entries with which to analyze the at least one patch based on a location of the at least one patch.

6. A method comprising:

acquiring, with a computed tomography (CT) acquisition unit comprising an X-ray source and a CT detector configured to collect CT imaging data, imaging information of an acquisition volume of an object;

reconstructing, with at least one processor, an initial image using the imaging information, the initial image including at least one object representation portion and at least one artifact portion;

identifying, with the at least one processor, at least one region of the initial image containing at least one artifact, and isolating the at least one artifact from desired image content by analyzing the initial image using an artifact dictionary and a non-artifact dictionary, the artifact dictionary including entries describing corresponding artifact image portions, the non-artifact dictionary including entries defining corresponding non-artifact image portions, wherein the non-artifact dictionary includes entries corresponding to true or accurate representations of anatomy and entries corresponding to random or uniformly distributed noise; and

removing, with the at least one processor, the at least one artifact from the initial image to provide a corrected image.

7. The method of claim 6 , wherein identifying the at least one artifact comprises identifying the at least one artifact using a weighted combination of an entry from the artifact dictionary and an entry from the non-artifact dictionary.

8. The method of claim 6 , further comprising:

dividing the initial image into plural patches;

subtracting a mean value of at least one patch from the at least one patch; and

analyzing the at least one patch using the artifact dictionary and non-artifact dictionary after subtracting the mean value from the at least one patch.

9. The method of claim 6 , further comprising:

dividing the initial image into plural patches;

analyzing at least one patch separately from at least some of the other patches, wherein the artifact dictionary entries and the non-artifact dictionary entries correspond to a patch size of the plural patches, to identify at least one artifact in the at least one patch;

removing the at least one artifact from the at least one patch to generate at least one corrected patch; and

combining the at least one corrected patch with additional patches to provide the corrected image.

10. The method of claim 9 , further comprising selecting non-artifact dictionary entries with which to analyze the at least one patch based on a location of the at least one patch.

11. A tangible and non-transitory computer readable medium comprising one or more computer software modules configured to direct one or more processors to:

acquire, with a computed tomography (CT) acquisition unit comprising an X-ray source and a CT detector configured to collect CT imaging data, imaging information of an acquisition volume of an object;

reconstruct an initial image using the imaging information, the initial image including at least one object representation portion and at least one artifact portion;

identify at least one region of the initial image containing at least one artifact, and isolate the at least one artifact from desired image content by analyzing the initial image using an artifact dictionary and a non-artifact dictionary, the artifact dictionary including entries describing corresponding artifact image portions, the non-artifact dictionary including entries defining corresponding non-artifact image portions, wherein the non-artifact dictionary includes entries corresponding to true or accurate representations of anatomy and entries corresponding to random or uniformly distributed noise; and

remove the at least one artifact from the initial image to provide a corrected image.

12. The tangible and non-transitory computer readable medium of claim 11 , wherein the one or more computer software modules are further configured to direct the one or more processors to identify the at least one artifact using a weighted combination of an entry from the artifact dictionary and an entry from the non-artifact dictionary.

13. The tangible and non-transitory computer readable medium of claim 11 , wherein the one or more computer software modules are further configured to direct the one or more processors to:

divide the initial image into plural patches;

analyze at least one patch separately from at least some of the other patches, wherein the artifact dictionary entries and the non-artifact dictionary entries correspond to a patch size of the plural patches, to identify at least one artifact in the at least one patch;

remove the at least one artifact from the at least one patch to generate at least one corrected patch; and

combine the at least one corrected patch with additional patches to provide the corrected image.

14. The tangible and non-transitory computer readable medium of claim 11 , wherein the one or more computer software modules are further configured to direct the one or more processors to select non-artifact dictionary entries with which to analyze the at least one patch based on a location of the at least one patch.

15. An imaging system comprising:

a computed tomography (CT) acquisition unit comprising an X-ray source and a CT detector configured to collect CT imaging data of an object to be imaged, the X-ray source and CT detector configured to be rotated relative to the object to be imaged and to collect a series of projections of the object as the X-ray source and CT detector rotate relative the object to be imaged; and

at least one processor operably coupled to the CT acquisition unit, the at least one processor configured to:

reconstruct an initial image using the CT imaging information, the initial image including at least one object representation portion and at least one artifact portion;

divide the initial image into patches;

analyze at least one patch separately from the at least some of the other patches to isolate at least one artifact from desired image content by analyzing the at least one patch using an artifact dictionary and a non-artifact dictionary, the artifact dictionary including entries describing corresponding artifact image portions, the non-artifact dictionary including entries defining corresponding non-artifact image portions, wherein the non-artifact dictionary includes entries corresponding to true or accurate representations of anatomy and entries corresponding to random or uniformly distributed noise; and

remove the at least one artifact from the initial image to provide a corrected image.