Method and system for correcting artifacts in image reconstruction

• US 8,731,266 B2
• Filed: 12/17/2009
• Issued: 05/20/2014
• Est. Priority Date: 12/17/2009
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Zeng, Kai, DeMan, Bruno Kristiaan Bernard, Thibault, Jean-Baptiste
• Primary Examiner(s): Ton, Toan
• Assistant Examiner(s): CORBETT, JOHN M
• Application Number:
  US12/640,936
• Publication Number:
  US 20110150305A1
• Time in Patent Office: 1,615 Days
• Field of Search: 382/131
• US Class Current: 382/131
• CPC Class Codes: A61B 6/03 Computed tomography [CT] echo-tomography A61B8/14
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/5205 involving processing of raw data to produce diagnostic data
• CPC Class Codes: A61B 6/5258 involving detection or reduction of artifacts or noise
• CPC Class Codes: G06T 11/005 Specific pre-processing for tomographic reconstruction, e.g. calibration, source positioning, rebinning, scatter correction, retrospective gating
• CPC Class Codes: G06T 2211/424 Iterative
• CPC Class Codes: G06T 5/00 Image enhancement or restoration

Abstract

Methods and systems are provided for correcting artifacts in iterative reconstruction processes. In certain embodiments, weighting schemes may be applied such that less than all of the available scan or projection data is utilized in the iterative reconstruction. In this manner, inconsistencies in the data undergoing reconstruction may be reduced.

Claims

1. An image reconstruction method, comprising the acts of:

accessing scan data acquired using a computed tomography system, wherein the scan data comprises temporally offset scan data;

computing a voxel-dependent angular weighting function corresponding to the scan data;

using the respective weighting function to iteratively compute a set of images from the scan data, such that the angular range of the data contributing to each voxel is made more uniform and/or the angular range is narrowed for one or more voxels;

independently reconstructing images generated based on the temporally offset scan data to generate one or more temporally offset images; and

combining the temporally offset images using one or more of averaging, addition, weighted combination, or Fourier combination.

2. The image reconstruction method of claim 1, wherein the angular weighting function is view dependent.

3. The image reconstruction method of claim 1, wherein the angular weighting function is one of a trapezoidal weighting function or a rectangular weighting function.

4. The image reconstruction method of claim 1, wherein the scan data comprises helical scan data.

5. The image reconstruction method of claim 1, wherein the images iteratively reconstructed with the weighting function have increased temporal resolution relative to images iteratively reconstructed without the weighting function.

6. The image reconstruction method of claim 1, wherein the angular weighting function is an angle-dependent weighting in which a higher weight is applied at a center view for a voxel, and lower weights are applied away from the center view.

7. The image reconstruction method of claim 6, wherein the higher weight has a value of 1 and the lower weights taper down to 0 for the views furthest from the center view.

8. The image reconstruction method of claim 1, wherein the one or more voxels for which the angular range is narrowed is limited to regions of motion.

9. An image reconstruction method, comprising the acts of:

accessing scan data acquired using a computed tomography system, wherein the scan data comprises temporally offset scan data;

computing a voxel-dependent angular weighting function corresponding to the scan data;

using the respective weighting function to iteratively compute a set of images from the scan data, such that the angular range of the data contributing to each voxel is made more uniform and/or the angular range is narrowed for one or more voxels;

jointly reconstructing images generated based on the temporally offset scan data to generate one or more temporally offset images; and

combining the temporally offset images using one or more of averaging, addition, weighted combination, or Fourier combination.

10. The image reconstruction method of claim 9, wherein the angular weighting function is view dependent.

11. The image reconstruction method of claim 9, wherein the angular weighting function is one of a trapezoidal weighting function or a rectangular weighting function.

12. The image reconstruction method of claim 9, wherein the scan data comprises helical scan data.

13. The image reconstruction method of claim 9, wherein the images iteratively reconstructed with the weighting function have increased temporal resolution relative to images iteratively reconstructed without the weighting function.

14. The image reconstruction method of claim 9, wherein the angular weighting function is an angle-dependent weighting in which a higher weight is applied at a center view for a voxel, and lower weights are applied away from the center view.

15. The image reconstruction method of claim 14, wherein the higher weight has a value of 1 and the lower weights taper down to 0 for the views furthest from the center view.

16. The image reconstruction method of claim 9, wherein the one or more voxels for which the angular range is narrowed is limited to regions of motion.