Second pass metal artifact reduction for moving and static objects

Dirk Schäfer, William van der Sterren, Michael Grass


Published in:Fully3D 2017 Proceedings


 Metal artefacts such as streaks and shading in Carm cone beam CT (CBCT) scans are often not caused by "photon starvation", i.e. there is still information in the metal shadow. Instead, the artefacts are caused by inconsistent lineintegral measurements between different projections (e.g. lateral and anterior-posterior). These inconsistencies have two main causes: First, inconsistent removal of scatter or other imaging deficiencies for rather big static high-contrast objects like screws and metal hip implants. Second, motion inconsistencies for rather small moving high-contrast objects like contrast filled vessels or catheters.
A newly developed two-pass method based on the subtraction of the registered metal shadow that is filtered with a matched 2D filter is presented. Good results in the case of moving and static ’metal’ objects are achieved.
Dirk Schäfer
Philips Research Hamburg
William van der Sterren
Philips Healthcare
Michael Grass
Philips Research Hamburg
  1. Z. Chen, X. Jin, L. Li, and G. Wang, “A limited-angle ct reconstruction method based on anisotropic tv minimization,” Physics in Medicine and Biology, Vol. 58(7), 2119, 2013.
  2. L. Feldkamp, et al., “Practical cone-beam algorithm,” J. Opt. Soc. Am. A 1, 612-619, 1984.
  4. D. Parker, “Optimal short scan convolution reconstruction for fan beam CT,” Med. Phys. 9, 254-257, 1982.
  5. F. Noo, M. Defrise, R. Clackdoyle, H. Kudo, “Image reconstruction from fan-beam projections on less than a short scan,” Phys. Med. Biol. Vol. 47, 2525–2546, 2002.
  6. F. Noo, S. Hoppe, F. Dennerlein, G. Lauritsch, J. Hornegger, “A new scheme for view-dependent data differentiation in fan-beam and conebeam computed tomography,” Phys. Med. Biol. Vol. 52, pp. 5393–5414, 2007.
  7. C. Riess, M. Berger, H. Wu, M. Manhart, R. Fahrig and A. Maier, “TVor not TV? That is the Question,” Fully3D meeting, p. 341-344, 2013.
  8. EY. Sidky, C. Kao, X. Pan, “Accurate image reconstruction from fewviews and limited-angle data in divergent-beam CT,” J X-Ray Sci Technol., Vol. 14, pp. 1–21, 2006.
  9. MD. Silver, “A method for including redundant data in computed tomography,” Med. Phys., Vol. 27, pp. 773–774, 2000.
  10. S. Wesarg, M. Ebert, T. Bortfeld, “Parker weights revisited,” Med. Phys.,Vol. 29, pp. 372-378, 2002.
  11. Z. Wang, AC. Bovik, HR. Sheikh, and EP. Simoncelli, “Image Qualifty Assessment: From Error Visibility to Structural Similarity,” IEEE Transactions on Image Processing, Vol. 13(4), pp. 600–612, 2004.