Effect of contrast magnitude and resolution metric on noise-resolution tradeoffs in x-ray CT imaging: A comparison of non-quadratic penalized alternating minimization and filtered backprojection algorithms

Joshua D. Evans, David G. Politte, Bruce R. Whiting, Joseph A. O'Sullivan, Jeffrey F. Williamson

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations

Abstract

Purpose: To assess the impact of contrast magnitude and spatial resolution metric choices on the noise-resolution tradeoff of a non-quadratic penalized statistical iterative algorithm, Alternating Minimization (AM), in x-ray transmission CT. Methods: Monoenergetic Poisson-counting CT data were simulated for a water phantom containing circular inserts of varying contrast (7% to 238%). The data was reconstructed with conventional filtered backprojection (FBP) and two non-quadratic penalty parameterizations of AM. A range of smoothing strengths is reconstructed for each algorithm to quantify the noise-resolution tradeoff curve. Modulation transfer functions (MTFs) were estimated from the circular contrast-insert edges and then integrated up to a cutoff frequency as a single-parameter measure of local spatial resolution. Two cutoff frequencies and two resolution comparison values are investigated for their effect on reported tradeoff advantage. Results: The noise-resolution tradeoff curve was always more favorable for AM than FBP. For strongly edge-preserving penalty functions, this advantage was found to be dependent upon the contrast for which resolution is quantified for comparison. The magnitude of the reported dose reduction potential of the AM algorithm was shown to be dependent on the resolution metric choices, though the general contrast-dependence was always evident. Conclusions: The penalized AM algorithm shows the potential to reconstruct images of comparable quality using a fraction of the dose required by FBP. The contrast-dependence on the tradeoff advantage implies that statistical algorithms using non-quadratic penalty functions should be assessed using contrasts relevant to the intended clinical task.

Original languageEnglish
Title of host publicationMedical Imaging 2011
Subtitle of host publicationPhysics of Medical Imaging
DOIs
StatePublished - May 13 2011
EventMedical Imaging 2011: Physics of Medical Imaging - Lake Buena Vista, FL, United States
Duration: Feb 13 2011Feb 17 2011

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume7961
ISSN (Print)1605-7422

Conference

ConferenceMedical Imaging 2011: Physics of Medical Imaging
CountryUnited States
CityLake Buena Vista, FL
Period02/13/1102/17/11

Keywords

  • alternating minimization
  • computed tomography
  • noise
  • non-quadratic regularization
  • resolution

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    Evans, J. D., Politte, D. G., Whiting, B. R., O'Sullivan, J. A., & Williamson, J. F. (2011). Effect of contrast magnitude and resolution metric on noise-resolution tradeoffs in x-ray CT imaging: A comparison of non-quadratic penalized alternating minimization and filtered backprojection algorithms. In Medical Imaging 2011: Physics of Medical Imaging [79612C] (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. 7961). https://doi.org/10.1117/12.876701